A/c Inop

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While I'm waiting for responses on my light bulb problems, I may as well post about my A/C. It doesn't blow cold air. I've tried topping off the freon, but it doesn't seem to be sucking anything from the can even with the vehicle on and the A/C on full blast. My sister once had it checked out, and they said it would cost about $300 to fix (I have no details on what's wrong, sorry). I'd like to confirm this for myself without getting it professionally tested again. If you have any ideas for dianosing the problems, please let me know. I will need very simplified instructions because I'm a total beginner in this.

Car: Toyota Camry '96 LE, Automatic shift, 4 cylinders.

PS: I'm having difficulty searching for past A/C topics, because it says "A/C" is too short to be included in a search, and of course people tend not to write out "air conditioner" in their posts (only found four topics with that).

Oh, I've checked the two A/C fuses located at the passenger side kick panel. They are intact.

posted by  JaneiR36

Check if your compressor clutch is engauging and if not, check if it's getting power to the clutch. If it's not getting power from there, go to the a/c relay and check if that is getting power on the coil side as well as the contact side.

Report back :thumbs:


posted by  DodgeRida67

Thanks for replying! But um... could you please idiot-proof your instructions for me? What instruments to use, how-to's, what the compressor clutch, a/c relay, coil side, and contact side are? (hopefully, there really are no minimum requirements for joining this site :laughing: ). I'll be doing some research in my Hayne's manual, but the truth is I've always had difficulty understanding it because there seems to be an underlying assumption that anyone reading it has an intermediate to advanced knowledge of cars.

I'm pretty sure anyone can help me from here on out, just in identifying the parts and such, and what to do with them. I really can't imagine anyone having less knowledge about cars than I do right now... :cry:

posted by  JaneiR36

I recall now that the extent of the Hayne's manual information on A/C is something about R-12 / R-134 conversion, and other than that they say it's outside the scope of their manual. I'm really going to need some help on this!

posted by  JaneiR36

Something has me worried. Before we get started answer something for me. You said you topped off your freon. What type does your car use?

posted by  DodgeRida67

well, I'll be. I'm just realizing that I've been assuming it was the 'environmentally friendly' R-134a, because the vehicle was manufactured after 1993. Are there any exceptions to this, and if so, how can I find out for sure? Yes I did try to top off the freon with a kit we bought from the auto store. We've used it on my Mom's '96 Accord and it worked just fine. I did have to use some kind of adapter provided in the kit for the Camry, so I'm now wondering if the fittings were not tight enough or didn't push the valve in properly to enable intake of the fluid. ARGH!!! I'm totally confusing myself!!

Okay, I also realize I did not mention an actual symptom. When you push the A/C button with the fan blower on, the little A/C light stays lit for about ten or so seconds before it starts flashing. Either way, no cool air comes out ever.

posted by  JaneiR36

Oh god. Just as I suspected.

never never never never never never n-e-v-e-r assume what type of refridgerant you should use. Not only is it very dangerous, it can ruin your entire air conditioning system and you'd have to change everything out. It would cost you about the same as a conversion would to fix. You shouldnt even use the same gauges when checking your refridgerant. In other words, don't use a gauge to check r-12 and r-134a, use two seperate ones. It's bad if you get the wrong refridgerant into an air conditioning system. In even minute ammounts.

Here's how you can know what to put in, go lift the hood. Look on your compressor and it should be either stamped on the housing or on a sticker. If not there, look on the compression and return lines. It has to be there.

After we get this cleared up we can get started I guess. If you've mixed the two types togethor on accident, I feel for you. :ohcrap:

posted by  DodgeRida67

R-134a. Whew! Dodged that bullet! I'm not even sure I remember why I used that adapter. If I recall correctly, the flange from the kit wouldn't fit on the 'low' A/C line... The kit is made by interdynamics, by the way. Have you heard of it?

posted by  JaneiR36

Ok good - no mix ups now. Since that's out of the way...

If you have up-to-spec refridgerant, we can now begin. First of all your going to need a volt meter if you don't already have one. My bet is you don't have power getting to your clutch in the compressor. So we need to check voltage at the compressor and work back to see where the break is.

Look at your compressor, on most cars the plug for the power to the clutch in the compressor is a two-wire clip right on the front, and top of the compressor. Right near the clutch and drive belt/pulley. Pull the clip off, turn a/c controls in the car to the coldest setting, max a/c that way you know the air should be on. Check voltage at the harness you just took off. Let me know if its getting any juice, and how much.

EDIT: P.S, when you test for voltage don't forget to have the car running! :thumbs:

posted by  DodgeRida67

YAY! Bought a multimeter.

harness reads 0.53 V

I decided to connect the leads across the battery just to be sure: 13.94 V

hmm... what's to stop me from just returning the multimeter and saying I didn't need it afterall? :wink2: DAMN GUILTY CONSCIENCE!!! :laughing:

hey Dodge rida guy, thank you for your patience :)

posted by  JaneiR36

OK that's not good news. I need more readings though.

I want the readings from the hot wire from the harness, to ground. Then I want a reading from the ground wire at the harness, to hot at the battery. Then I want OHM (X1) between the two leads in the compressor( where the harness plugs in) Be sure not to put the OHM setting on, and put any voltage at all to the test leads of the meter, if you do, you will ruin it! So when it's on OHM reading, make sure you understand what you need to do with it: The leads go on the compressor, not on the harness you unplugged.

Just to make sure of something, when you took voltage readings from the compressor, you did hook the test leads up to the wiring harness you unplugged ( that runs through your electrical system) and not at the compressor right? That could throw us off if you get that turned around.

If you have any questions about what I've said dont mind asking. Just remember; there are no stupid questions, just stupid answers!

Don't worry about the multimeter, it will come in handy many many times. It was a good investment. I'm glad you got a digital one (sounds like you got a digital ones since your readings went into the tenths and hundreds) because you can test sensors with that. Analog meters will ruin sensors because of the current it needs ( very little ) to energize the coil and move the measurement needle.

posted by  DodgeRida67

hot harness to ground harness: 5 mV

hot harness to ground battery: 0.48 V

ground harness to hot battery -5.5mV, I suppose

ohm compressor (with car / AC off, no need for any voltage whatsoever and compressor is also disconnected): 106 ohms

posted by  JaneiR36

oh yeah, the compressor harness actually has three wires. I just assumed the black one is ground and the other ones are whatever... At some point I was just taking readings and recording whatever was a non-zero value... Shoddy work, I know, but I just thought I should mention in case it was important (hopefully it's not).

posted by  JaneiR36

Good close reading to each other. (5mV and 5.5Mv) The reason it showed -5.5 is because you hooked the leads up backwards. In other words, you put the negative test lead on a hot power source, and a positive test lead on a negative power source. But don't worry about that.

We found our problem. 106 OHMs in the compressor clutch coil. You didn't miss a decimal point right? It should be about 5 OHMS. Assuming you hooked it up right and had it on the right setting. 106 OHMs, the thing is fried! your going to have to take the clutch out and test directly at the coil itself to confirm this is the problem. Also your probably going to have to replace a fuse in the fuse box probably.

The new clutch (if we confirm it as the problem) will cost you $100 for the part.

posted by  DodgeRida67

What colors are all the wires? (black is usually hot in an automobile)

posted by  DodgeRida67

Black, red, and blue. (all three spliced with white).

So would I need to do about this cluth? I need those idiot steps again for disconnecting, etc. Right now I'm thinking take out the whole compressor, which I'm guessing is not what you mean. Would I be able to drive around with the compressor out? There's that belt around it and all... it would need to be connected to something, right?

posted by  JaneiR36

The compressor stays in ( thats better news than you think trust me. )

In the center of the compressor pulley, you will see a bolt. All you do is take out the bolt and pull off the pulley, clutch and coil all at once ( in 3 pieces)

Pictures are worth 1,000 words!

Your compressor: (Hopefully!) There should be a bolt in the front and center of it. Take it out.

This is what you wil be taking off when you take the bolt out:

Clutch, Pulley, Coil

Ill explain how this works.
Since the compressor has no need to turn everytime the engine does, as it will cycle on and off, you need something to let it become free from the engine turning. Clutch!

The clutch works like this. See the pulley? It spins all the time with the engine. The clutch ( in the front) does not. When energized, the coil creates a strong magnetic field ( coil is behind pulley ) which pulls the clutch (front) into the spinning pulley. Now the clutch is spinning! the clutch is mounted on the compressor shaft so now the compressor is turning. :thumbs:

What I think is happening: I think the coil is not getting energized so the clutch is not engauging therefor the compressor is not spinning and boom no cold air for you. I think the coil is fried. Should be 5OHMs not 106OMHs. That is if the measurements you took are correct and were taken at the correct spots. You need to take it off and check it again though.

posted by  DodgeRida67

wow... look how clean and shiny those compressors are :wink2:

Dang it! I was so excited to continue working on this, but we park our cars outside and it's dark now. Okay! I'm off to Walmart to buy some bulbs... for the lamp on our lawn. They've been out forever but no one particularly cared... until now.

What do I do with the pulley, clutch, and coil once I take them out? If I'm able to accomplish that step tonight, I'll be wondering what to do next. Take the resistance measurements again?

posted by  JaneiR36

We need to get ahold of a wiring diagram from your compressor clutch so we can actuatly test OHMs in the coil. If you do that, you won't have to take the coil out to test it. I'll be back tomorrow night to help. Do some research for the wiring until then. Someone around here will probably help you. Ill be back...

posted by  DodgeRida67

well I'm really grateful for your help so far :) It's still too dark to work outside, so I won't be taking anything apart until the morning. Hopefully I'll gather some more information by or before tomorrow. Thanks again!

posted by  JaneiR36

can someone share any resources for possibly finding these wiring diagrams? So far I've looked at Hayne's and Autozone's, and neither contain diagrams of the A/C system. Later today, I'll be stopping by the Toyota dealership to see if their repair manual contains this information, but other than that, I'm all out of ideas.

posted by  JaneiR36

The shop manual for your car will have the information. It really should.

posted by  DodgeRida67

Here's my :2cents:

If you are that much of a beginner that you cannot understand the simplist of troubleshooting techniques for this problem nor identify the a/c system components involved, you really are not going to be able to fix this problem yourself. I did not even read all the follow up posts to the original problem description, but we'd have a book hammered out by the time it was all said and done. Take the car to a shop, get it properly diagnosed and call it a day. You'll save yourself the time and efforts of much frustration as well as those of us who want to help, but havent the time to start from ground zero and build up to mechanic level. I like to help people but if you dont the know the first thing about what you are dealing with, then that's too much typing and too much work.

I agree with dodge's first advise on what to check because you did not tell us any of the information that we'd need to know regarding the actual problem description. Good luck

posted by  cmeseadoin

So far JaneiR36 seems to be following well and having fun doing it. Dodge seems to be having fun helping and other A/C newbies may be learning from reading the thread.

Oh and the lawn lights got fixed!

I'm waiting for the next installment to see how it prograsses.

posted by  HighWayMan

Well then MORE POWER TO THEM, right? :clap: :clap: ....I always vote for efficiency :banghead:

posted by  cmeseadoin

I'm replying to three posts at once, I hope that's okay.

Yes, I called them this morning. $118. I'm working on some other options, but I'll let you know as soon as I get a hold of those diagrams. I'm just remembering one of vwhobo's posts that said to insist on a free repair manual whenever you buy a car. I guess I'll keep that in mind for the future.

That about sums it up! I've driven around with the A/C broken for three hot summers, including one road trip to Florida. So I don't know what to say, other than I've got plenty of time, and am willing to spend maybe up to the amount it would have cost to have a mechanic fix it.

I really do understand the underlying frustration in trying to help out a complete newbie (hey, I wonder if there's a status lower than CF newbie mine can be changed to; I'm just not sure I'd want "CF idiot" staring me in the face each time I logged on :) ). That's why I continue to profusely thank Dodgerida and everyone else who continues to help me out.

cmeseadoin, it won't necessarily take a whole book (just a ridiculously long thread :wink2: ). "All-there-is-to-know-about-air-conditioning" can be compared to an extremely complex network diagram. But through the process of elimination, the number of steps involved in solving my very own problem could be considerably shortened. I'll keep your advice in mind, though. When I'm all out of options, there'll probably be nothing else I can do.

Finally, I hate to get on the defensive, but I must add that I followed the rules of the forum and did not mislead anyone as to my level of expertise. I can only assume that if you're reading and getting frustrated, you are doing so by choice.

posted by  JaneiR36

Jane, I complete admire your attitude and in going back reading the threads, I see that you do understand the stuff and you are learning it. There is nothing wrong with that at all. You're not an idiot at all and I never meant that you were. I think it is great you are learning.....I just spend lots of time in here reading what some people type and so from my end, sometimes I think to myself "oh GOD, another one of these that's gonna take forever and they are not going to be able to understand." You seem to be doing well so perhaps I typed that prematurely and I should not have. Go for it and again, I totally understand and respect your view on things. Personally, I pay no one to do a thing for me. I either know how to do it already or I learn as I go and I challenge myself, so really I do understand. I find that when you pay people, like contractor to come to the house to do things or mechanics, all they want is your bucks. They want to come in, take a ten day job, do it in one day and get the check. They have no work ethic, they are damn near crooks and they DON'T know ANY more than I do. So hell yeah I agree with you....sorry for the premature judgement....that is one of my faults and I am more than willing to admit it in this case because you've obviously proven yourself otherwise!! :smoke: I just see many of the "other" cases in this forum so that is why I made those remarks. Good job and good luck with it!!! Sorry for judging when I should have done more homework first! :-)

posted by  cmeseadoin

$118 bucks for a shop manual. I'm going to have to pay $180 for my new truck, so thats not bad. Last time I bought one cost me $60.

If you plan on doing your own repair work in the future like you are now, get the manual. If not don't sweat it.

We need to get a wiring diagram for the compressor clutch though to test it right. If you did by chance test it right, at 106 OHMs the clutch is defintaly bad. Idealy it should be around 3.5 OHMs.

I'm going to pay a visit to Advance auto parts today and I'll see if I can look in a Hayne's book and find that diagram.

posted by  DodgeRida67

Bad news - no luck with the Hayne's manual. (although I did find one I needed :laughing: )

I say you should call some garages and ask them which wires to use to test the OHMs in the clutch coil. It's either that, internet searching, or buy the shop manual.

posted by  DodgeRida67

before you spend your money...

go to advanded auto parts or autozoo(autozone)
and see if you can buy just the a/c clutch or if you have to buy the whole compressor if you can buy the clutch keep going but if not pay the 300 and get the pro to do it compressor's really are tough and your going to have to pay to have your system evacuated by a pro anyways...

note to cm: I'm a mechanic student right now and I honestly believe when I get out in the industry that i will earn every penny I make

posted by  Pieface

Well Pieface, you go big guy...just a few words of advice first. Before you "get out in the industry," make sure you learn way more than you seem to know on this forum. Go back and read some of your postings (particularly with a/c) and I can tell you that you have typed information that is totally incorrect or made assumptions that are not necessarily true. You cannot take a problem, particularly online and with NO other information to go on, and roll it into a bunch of assumptions and then type an "if this then this" statement and expect people to buy it. It won't work and I can't stand it when people do that on here. You are supposed to take what the person types and ask probing questions so that you can help them narrow down where the problem might be....AND ALWAYS remember if the car ain't in front of you, you can't promise anything to anyone.

Because you've demonstrated that you are not a deep thinker and you are giving very shallow advice which may or may not help someone , you'd not touch a car of mine with a ten foot pole. Good luck, you've got a lot more learning to do before I'd consider you a mechanic. You're like the ones I cringe at the thought of making statement like: "Well, if the compressor doesn't come on when you press the button and you don't hear the engine rev slightly to compensate for the HP draw, then you might as well pay a professional to replace the compressor." Sound familiar? What kind of advice is this? Surely they teach you in automotive school that there are MANY things that could cause a compressor to not engage short of the compressor being bad? Use your head and THINK a little more than that.

posted by  cmeseadoin

JaneiR36, please disregard everything Pieface told you.

And for the record, you can infact buy the compressor clutch. They are around $100.

posted by  DodgeRida67

Dodgeman, I just figured we still don't know what part's broken for sure. Just to let everyone know, I'm reading all the responses but probably won't (really, can't) be doing anything else until I get the manual.

cm... thanks for your kind words earlier :)

posted by  JaneiR36

No Problem Jane..... :) Seems like you are well on your way to figuring this thing out. One note which I am sure you have gleaned thus far from this forum.....make wise decisions about whose advice you follow in here. Pieface, for example, is giving directions that are not worth their weight in salt. I am sure you read my dissertation on that from above but it just kills me when people come in and type out one liners saying, "OH YEAH, you definitly need a compressor if it doesn't come on when you push the button." These people are ignorant, ill-informed and to a degree, stupid. If you were to follow his advice before a proper diagnosis, you'd be spending 100's of dollars perhaps all for nothing. So just be forewarned. Look at the depth of advice people give you and the logic. You're doing fanastically for someone that claims to "not be a car person." :hi: After all this you've done, I'd let you work on my car WAY before Pieface would touch it. Hell, his screename tells me all I need to know about him. (Ie. YOUNG, DUMB, and ill-educated, yet thinks he's a mechanic.....just read his postings and you'll see that thought is SCAREY) Pretty much sums it up!! Good luck Jane and we'll continue helping as you work!

posted by  cmeseadoin

Jane try the public library. Most have a good selection of auto books, some will even have your car model. Haynes and Chilton both have books with wiring diagrams and A/C.
You can't take them home but you can copy all you want.

posted by  jcutsh

Hayne's doesn't have an A/C wiring diagram. My library had a Chilton's manual, but not for my year. I checked it out, anyway, just to get familiar with what the circuits might look like. Currently I'm waiting for shipping of a manual I ordered online - 20 bucks off of ebay. From the description of this product (it's on CD), it may or may not be legit, but it's still a hell of a lot better than spending $118. I'll let you all know once it arrives.

posted by  JaneiR36

Hope you all don't mind me jumping in on this thread.
I'm having A/c trouble on a 97 Mustang. I'm looking at it for a friend. She was told by a Ford dealer it would cost $1500 just in parts. They said it needs a new compressor, accumulator and lines. I found the parts online for under $500. So i don't trust them. Anyway, friend says A/C worked great, car sat undriven for 3 days then started blowing hot air.

Used voltage meter like you posted.
Disconnect harness at compressor and messured only 0.02v
Hot harness to ground was .08
Neg. harness to pos. battery is 13.89v
Ohms at compressor was 3.8 ohms

All these were the same with the A/c on reg. or Max. and in the off postition.
Fan blows a lot harder when I put it on Max A/C (seems like the switch is working) but all votage readings stays the same at compressor harness.
any info would be great?

posted by  smfg

**ego boost** :clap:

posted by  BavarianWheels


Anyway, JaneiR36, did you see where smfg said "Ohms at compressor was 3.8 ohms" That's what you should be getting. You said you got over 100 OHMS. Bad news....

So obviously, smfg, you know how to test the compressor OHMs.(clutch OHMs actually) please tell us what wires or terminals to test with our OHM meter at!

posted by  DodgeRida67

DAMN. Do you get what you pay for, or what? I ordered that (probably) BOOTLEG manual almost two weeks ago, and I still haven't seen it in the mail. It might have arrived today (just like it "might" have arrived any number of days in the past two weeks), but of course mail doesn't get delivered during a USPS holiday.

When I ordered my operation manual from Toyota, they had it on my doorstep within two days. This really SUCKS that you have to pay so much just go get an item delivered on time.

Anyhoo..... still waiting on the repair manual. Was losing interest in continuing on the work for a while there, but I've got my second wind now!

posted by  JaneiR36

Ugh. They sent me a second manual in the mail when I complained about not having received the first one. I still ain't received either one of them.

By the way, did ya'll ever get around to helping smfg? I think s/he needed some help but wound up being asked to give it (to me). Please don't forget to help him/her if you can.

posted by  JaneiR36

SMFG will start a new thread if they want assistance with a problem. There is not enough time in a year to seek out previous threads where people "chime" in and post their problems within the dialogue of someone else's. If someone can help at the time, that is great, but the only way to be recognized is to start a new thread with what you have going on as well as all the info. you have for your issue.....AFTER you introduce yourself of course! :thumbs:

posted by  cmeseadoin

So I finally got the manual (is that an echo I hear? he he...). Anyhoo. Here a drawing of what I understand to be my compressor (or clutch?) terminals:


If you recall the colors I described before, they seem to match with the wiring diagram. So I measured the resistance between the terminal connected to the black wire (on the clutch, not the harness itself) and the negative terminal of the battery. After a little jumping around, the resistance finally settled at 4.5 ohms!!! WOOHOO!!!!!

Okay, if any of you all are still reading this thread (a very special someone has threatened to leave at least five or six times since I've been here :laughing: ), what do I do now? Thanks again!

posted by  JaneiR36

So 40-some odd posts later, I finally finished up the first instructions :laughing:

I measured the voltage at the AC relay. Here is a circuit diagram:


The second readings, if any, are the readings when the AC is turned on:

1 - 13.59 V, 14.43 V
2 - 0.16 V, 0.45 V
3 - 14.75V, 14.57 V
5 - 0 V

I honestly don't understand why 1 and 5 are not exactly the same. I know if the wires are connected, there would be a splicing symbol, but where else could that exiting from pin 5 be going? So I've got the readings, but can't quite interpret them. Please help!!!!!

posted by  JaneiR36

Alright! A WIRING DIAGRAM! WOOOOOO! Just what we needed. OK - so now we know the clutch is OK.

Now we need to test the relay. So I'm going to need more readings (didnt i tell you that meter would be usuful more than once)

I need voltage between wires 1 & 2. If you get a voltage reading lower than 11 volts, turn the car off, disconnect the ground terminal on the battery and measure OHMs between wires 1 & 2.

After this test, if you have voltage (higher than 11 volts) at wires 1 & 2 ( with the a/c controls on) you should have voltage at wires 5 & 3 at the same time. if you have voltage in wires 1 & 2, but not 5 & 3, your relay is fried.

EDIT: If you don't have voltage at wires 5 & 3 when you have voltage at 1 & 2, try measuring from 5 & a good ground. ( just to be 100% )

posted by  DodgeRida67

Oh yeah, and measure between 5 & ground. You should have good voltage there. If not, things are going to get sticky... (make sure a/c controls are ON when you do that measuring!)

posted by  DodgeRida67

had to spend a good while looking for tools, but I finally got the readings. I don't know if I messed up before, but now, what I'm getting is:

V12 = 12.52 V, or something like that

R12, with negative battery disconnected, seemed to be 115 ohms at one point, but then I couldn't get any readings anymore and only got that "-1" on the meter

Then I turned the AC back on, and this time:

5 = 14.71 V
3 = 0.55 V,
2 = 0.52 V
1 = 14.78 V

So basically, at the top of the circuit (1 & 5), the readings are high, and underneath, they are low.

EDIT: I'm just realizing I shouldn't have disconnected the negative battery terminal because my V12 reading was higher than 11 V. Also I thought I would mention that all the individual readings are actually from the specified terminal to the negative battery terminal!

posted by  JaneiR36

no no no, I didnt want the readings from a wire number to ground. What I ment when I said something like "I need the reading between 1 & 2" was, that means measure from one and two. One test lead on wire number 1 and the other test lead on wire number 2. Not from 1 to ground and then from 2 to ground.

P.S: If you get a negitive reading while testing voltage, switch polarity.

posted by  DodgeRida67

But you can get those from the readings she measured... if the reading from 1 to ground is 14.78 V and the reading from 2 to ground is 0.52 V, then the reading from 1 to 2 is 14.78 V - 0.52 V = 14.26 V

posted by  kanato

It doesn't work quite like that.

posted by  DodgeRida67

It does... I've taken and taught a few classes on electric circuits, and I assure you that it does work that way. Usually there's small variations in measurements due to the quality of the multimeter used, but that's it.

posted by  kanato

V12 = 12.52 V = voltage between terminals 1 and 2. Drats. Wish I had made that a little more clear before. I'd been looking forward to your comments all day. So what's the verdict on the relay?

posted by  JaneiR36

OK voltage between 1 & 2 is good! So that eliminates all the controls in your dash, some sensors, and most fuses.

Now here is what I want you to do. Measure voltage in 1 & 2 again, and if you get the good reading (around 12 volts) then measure voltage between 5 & battery ground (this time do it to the battery ground :) ) and from 3 to ground. All 3 of these readings should be very close to each other. Around half a volt difference maximum.

If you don't get similar voltage readings, or no voltage ( especially on 3 to ground) then im sorry but your relay is fried. However, if it all checks out fine, then it's back to the compressor for one voltage reading, and if that voltage reading is fine, then it was your clutch coil all along.

posted by  DodgeRida67

5 = 14.71 V
3 = 0.55 V,
2 = 0.52 V
1 = 14.78 V

All readings between that terminal and ground, with the AC and blower turned on. Is an AC relay really around 80 bucks? That's the price I saw on the Autozone website.

posted by  JaneiR36

Just to make sure ( dont want to tell you wrong ) when you tested these, you did have the black test lead on the battery ground and the red test lead on the wire number right? I'm sure you did, but just verifiy.

If you tested right (like what I said above) your relay is fried. About the cost of the relay, I dont know what the cost is. But 80 bucks sounds ridiculious. If you decide to spend the money on a new relay, make sure you test OHMs again on your compressor clutch, because if OHMs are to high, it could burn out your brand new relay. Shouldn't be over 5 OHMs. :thumbs:

posted by  DodgeRida67

Yes, black on battery ground and red on test lead. YAY!!! Thanks!!! I'll be checking out a new relay, but more importantly, taking the clutch resistance reading again. Since the relay is really not supposed to be expensive, I hope my possible mistake doesn't cost me............................... eh... I'm sure it won't :)

posted by  JaneiR36

Well, the relay was inexpensive, but changing it didn't fix the problem. Thankfully, the dude at the dealership said I could bring it back so long as it was in the little bubble baggie with the barcode & price tag attached to it.

But you know, he pointed out something: that I could measure the voltage going into the relay, but not the actual voltage at the relay when the coil energizes and the switch closes and it's in operation (because you actually have to take the relay out to measure those readings, hence I really would just be measuring the voltage across an open circuit).

So I decided to leave that relay in, and measure the voltage at the next point connected to pin 3 of my AC's relay, and of course that would be the compressor harness, and also pin 1 of an identical relay, but for "Fan No. 3." Strangely enough, those voltages now read just zero. Not even the small voltage that was present at pin 3 of the AC relay. Ack. Something is clearly wrong after the initial point (where pins 1 and 5 have full and complete voltage). At this point I just feel like we've left no stone unturned and can't quite imagine what else can be done. Oh, and the compressor coil keeps coming in at 4.9, 5.0, 5.1 ohms. I have no idea what else to check.

Oh yeah, one more symptom I just noticed today, is that the engine actually revs a little higher when you first turn on the AC, then the sound goes down again and that's when the AC light starts flashing. I don't know if that's the compressor or just a fan kicking in, but that's what happens.

posted by  JaneiR36

I'll say one thing, this isnt making any sense. Relay didn't help at all, but all signs were showing the relay coil was energizing, but the switch wasnt closing, hence no voltage between 3 and ground. :screwy: Maybe the relay was bad, but it wasn't the only thing that was bad. :ticking:

posted by  DodgeRida67

ALRIGHT! OKAY! I'll give you sense!!! (Homer Simpson style... he he :laughing: ). Actually, I've got some pretty interesting readings now (how many readings does it take to measure one damn relay, you say? :wink2: ). Okay though. I finally got the common sense to hook some wires undeaneath the relay, so I could take relay voltages with the relay part still in. Turns out there has been voltage on pin 2 (base of the coil) all along.

Now for pin 3 (other side of the switch), things get interesting. Remember that revving sound I mentioned in my last post, where the engine revvs a little more for like a second or two and then that revving sound shuts off. Well, turns out that would be the relay switch getting activated for just a second. With GOOD voltage (14.something). And then it would go off. So obviously that relay is working (because this repeatedly happens), but the AC system is not liking something and keeps instructing it to shut back off. But what could this be?!?! PLEASE don't tell me FREON, or I will have to KICK somebody :laughing: Actually, please, oh, please tell me anything that could be wrong! I'm so damn close to fixing this!!! :)

posted by  JaneiR36

So you do get voltage on 3 to ground for a second huh then it goes away? That's good, I thought I was losing it for a while there. Kinda feeling bad for telling you wrong, but it seems like its not my fault, it's some malfunction. It's hard to diagnose online. Smart thinking on what you did.

Anyway, there are a handful of things that could be wrong now. You should, however, start with testing the freon.

posted by  DodgeRida67

Low side pressure = 85 psi. I've read something like 25 is where it should be at....... would the AC shut off because of too high pressure? hmm....... Also, I can't seem to locate the high side, so I don't have any readings for that.

So that revving sound was just the engine cooling fans, and not the compressor. I was looking at the compressor as the AC was running. All the belts and everything seem to be moving (with no change whether or not the AC button is pressed). Oh well.

posted by  JaneiR36

If the AC has been off for a while, the high side and the low side will come to equilibrium at the same value... the low side should be around 25 when the A/C is on.

You should have a low-pressure cutoff switch somewhere in there.. if you have an accumulator type system it will probably be on the accumulator. What this switch does is if it senses that the pressure is too low in the system, the switch will open electrically and cause the compressor to not run. It sounds like your freon charge is ok, so it's possible that switch is faulty. You can test that by turning the A/C controls in the car to max while the car is running and jump that switch... if the compressor starts to operate, then it is likely that the switch is faulty.

posted by  kanato

The best way to test a switch like that is to make sure you have enough pressure to close the switch, and take an OHMs reading.

posted by  DodgeRida67

jumpering the A/C dual pressure switch does nothing for the compressor. But it does cause the two fans to run without shutting off intermitently as before.

DodgeRida, do you mean ohms reading across the switch terminals? I'm not sure how else to make sure I have enough pressure. I actually tried measuring the pressure on the high side, but the freon coming out from there is a LOT cooler! Almost painful to the touch. The stuff coming out from the low side was pretty much just air that had a light scent to it.

posted by  JaneiR36

Yes. This switch should be good though, if it wasn't you shouldnt have had voltage at the coilside of the a/c relay. Test it anyway, because I've seen crazy things happen before.

posted by  DodgeRida67

990 ohms or something like that (that's of course with the switch completely out; that's the only way I could measure the resistance reading).

But get this. With the switch out and the AC running, the AC light actually stays on without turning off and blinking like before. The car seems to pulsate a little more, but still does not cool.

I think the compressor might just be running the entire time. As in it's not shutting off at all. Is that possible, or am I just not knowing which one is the compressor pulley and what not?

posted by  JaneiR36

The switch needs to be installed when you test it. But I'm assuming when you say "thats with the switch completely out" you ment jyst the harness (wires) off the top of the switch. because if the switch is out, it's obviously going to be open. But what you checking for is for it to be closed, which it will do (or should do) when you have proper pressure.

So the compressor may have been on the whole time? :ohcrap: If the compressor is on, the entire front of the thing will be spinning. Nothing up front will be stationary.

posted by  DodgeRida67

You can try measuring the voltage across those two terminals, with the switch in and enough pressure in the system. If the switch is open, as it should be, there should be no voltage difference between the two terminals.

It sounds like there may be a control problem somewhere, or some switch that it detecting something wrong and shutting off the compressor. I don't think the compressor is on all the time because there exist a variety of switches wired in series just to shut off the compressor. If the compressor is on all the time, then we need to measure the low side and high side pressures. The bad news is if the compressor is engaging and the low side and high side pressures are about the same, 80-100psi, then the compressor is probably shot.

Also check and see if there is a temperature difference between the two pipes going into the firewall from the engine compartment. Check to see if there is a temperature difference between the inlet and the outlet of the condenser. The inlet of the condensor should be the line that goes from the compressor up to the top of the front of the car, and the outlet should come out of the bottom of the condensor.

Do you know if your system has a receiver/dryer or an accumulator? A receiver/dryer is usually located after the outlet of the condensor before the firewall, which is on the highside or liquid side of the system. An accumulator will be on the lowside, and it will probably be where the lowside port is located.

posted by  kanato

I'll try to get the high side readings (already mentioned some difficulty I was having getting the pressure on the high side; is it safe to press the little thingie against the high pressure opening when the freon is so cold and seems to be at such a high pressure?)

Yeah the switch is alright. Voltage at both terminals is like 14.something, even without the AC on. When the AC comes on, it drops to like 13.something.

Dodge, yeah, all the visible parts of the compressor / pulley appear to be moving.

kanato, gimme at least a day to research your additional questions (took me 10 good minutes to confirm the location of the pressure switch), and when you say temperature, do you mean to the touch, or actually take a temperature reading?

posted by  JaneiR36

You really need a set of manifold gauges to read the high side. The connector should be a bit larger than the lowside port. I think you can probably rent a set of gauges at autozone. But let's check the other things first.

The temperature differences should be fairly large, under normal operation, so you could probably do it by touch. But if you have a thermometer handy, that would be better.

Also, I noticed that you said that the A/C light was blinking? Somewhere, there should be some reference as to how to turn that into useful information. But I'm not coming up with much on a Google search. Do you have any owner's/repair manuals that might shed some light on that?

posted by  kanato

petethegreek---First of all , without a set of guages there is no way of knowing what high and low side pressure is. If you know what the pressure readings are then you generally know what direction to go in. Sight unseen , it is almost impossible to diagnose a symptom without any info . All these suggestions that you have recieved are just educated guesses.You cant even begin to imagine how many diff. problems can cause your symptoms. Even though you don't want to spend the $ to have it diagnosed , that is the best way. And by the way , you must be certified to handle refrigerant. Oh, and one more thing, you mentioned earlier that you " topped off the freon" . How do you know how low it was and how much you added? The only way of knowing this is with a scale under your refrigerant tank, or with a premeasured amount, or by monitoring pressures as you fill, and if you had to add that means that there is a leak, if there is a leak that means there is air and contaminants in the system. As you can see there is alot to an a/c system , and thats just the tip of the ice-berg. Bottom line, TAKE IT TO A CERTIFIED REPAIR FACILITY AND HAVE IT DONE RIGHT , " ONCE "

posted by  petethegreek

You could probably say most of this about anything anyone posts on the Repairs & Maintenance forum. Of course if someone hasn't looked at the car they're going to have a hard time giving more than an educated guess. But I think what we're trying to do is at least narrow the scope of the problem down. There are some very complicated things that could be wrong which require expensive equipment to fix (ie. compressor failure requiring refrigerant recovery & evac in order to replace) and some very simple things that could be wrong (ie. relay switch), stuff which does not require openning the refrigerant system up. If she has to take it to a mechanic, it'd be nice to know what kind of things the problem could be so there's no rip-off involved, because some mechanics can be quite unscrupulous.

posted by  kanato

Unfortunately, the manual I have is electrical only. (Turns out the whole thing wasn't $118, that was just for the mechanical repair manual, there was another one for electrical, and a third for automatic transmission or something....... and since I needed wiring diagrams............)

What they did mention in this one, though, is that the AC mag relay switch should be closed with the ignition, blower, and AC switches on. So far, the first two are definitely working. The third seems to be working from our readings, but something does get shut off.

They've also mentioned that the dual pressure switch would be "open with pressure 30 psi or above 384 psi." What does that mean, really? I'll look into renting the manifold gauges, but I'm already getting the general impression that the high side pressure is much higher than the low side. Maybe the estimation should help a little? The pressures don't seem to have equalized as originally thought.

petethegreek, while your suggestion is by no means original (yes, even on this thread!), I do seem to be nearing the end of my rope. If I don't have this diagnosed and fixed when it starts to cool off, I'll either shut down the project till next summer or just get it fixed professionally. Happy? :)

posted by  JaneiR36

Obviously high side pressure is high and low side pressure is low, that's where they get their names. :laughing: :thumbs:

OK - it's a switch as you know. If a switch is "open" it is off. If a switch is "closed" it is on. So if the pressure drops below 30PSI the switch will open (go off) or if it reaches pressures above 384 is will go open. Anything in between and the switch will be closed (on)

petethegreek, it is recommended R134A refridgerant be handled and used by a licenced person, but is not enforced nor is it the law. After all, R134A is used to blow out the keyboard your using which you can buy at any office supply shop. Since when do service shops do jobs "right"? If people never learn anything they will get ripped off their entire lives. I'd hate to pay a mechanic for every problem I had.

posted by  DodgeRida67

From looking at http://www.epa.gov/oar/caa/caa609.txt, it seems that it's required by law that the person handling the refrigerant be certified when "servicing .. for consideration," that is, being paid for the work. If they were really serious about making even DIY type people be certified, then you couldn't go into walmart and buy cans of R134a whenever you like. And I've had quite a few service shops screw things up. I totally agree with DodgeRida67 here.

Under normal operation, the low side should probably be about 20-30psig and the high side should probably be around 200psig. Since we don't seem to have normal operation, it's something worth checking into. But check the temperatures first, since it's easier.

posted by  kanato

okay, I finally touched the inlet and outlet of the condenser (after running the AC for at least five mins during an errand). The inlet (from the compressor) seems to be of room temperature, not cold but maybe a little cool. The outlet on the other hand was hot. Not scalding hot, but still quite hot.

I have a receiver / dryer system. The receiver is actually where the dual pressure switch plugs into. I just didn't know what it was :)

By the way, is it possible that my pressure switch is supposed to be open during normal operation of the AC? My manual shows all switches in the off position, and this particular switch is drawn as closed.

posted by  JaneiR36

If your pressure switch is open, then the circuit to the a/c relay is open. When that happens, your relay is open. Which means no power for your compressor clutch. Which mean's your compressor will not engauge.

posted by  DodgeRida67

Okay, I drew a part of the AC circuit (tried to take pictures, but it just wouldn't come into focus!) Anyway, the pressure switch seems to be in parallel with the compressor clutch and stuff:


I wish I had more information from that "A/C Amplifier", it's just shown as a box. Basically, the pressure switch sends a signal to the amplifier and then the amp does whatever it wants with it. That's some detail I just don't know. Again, their drawings are all shown in the "off" position, so that switch might be off! (ie, closed is off, and open is on).

And kanato, the blinking light on the switch would be on the "AC switch" circuit (I can't believe I missed that before). The LED would be what blinks, but again, the circuit ends in the AC amplifier and I don't know how that part affects it.

posted by  JaneiR36

apparently, current always flows through the dual pressure switch so long as the ignition is on. Oh well.

posted by  JaneiR36

hey guys! I fixed it! I found the loose wire and spliced it!!!

==== Short version ends, long version begins :laughing: =====

Other than a couple hopeless attempts here and there, this final try began when I gave in on Saturday and decided to get a compressor clutch from Autozone. I found a deal for a remanufactured clutch for just $47.99. However, with this clutch in my hand, I could then repeat the coil resistance measurement, just for a baseline on what a good one should be like. I started by measuring just in between the two terminals. The numbers were ridiculous. They kept jumping around erratically, all the way from the hundreds, down to 13 or 14 ohms. I finally realized that one of the terminals was in fact grounded on the installed clutch (I did some voltage measurements to verify this again). So again I measured from terminal 1 to ground, and it came out to be 4.5ohms. Good, right? Well, the one I have measures just the same. So again, it's not the clutch. So a little depressed as I was, I realized that I have a good clutch, and from previous testing, the AC magnetic relay is actually getting energized.

So my next test was to check for continuity. Honestly, at this point I just figured a wire was fried. It was fried and I'd have to rip it out from the harness, and then replace it and tidy the harness back up.

The first part of this testing was to measure the resistance between the harness coming into the clutch and pin 3 of the AC magnetic relay. This was fine even without the relay in, because that part of the circuit should be continuous. No reading on the multimeter. So obviously, now I have to find some kind of midpoint. So what was that harness to harness connector called, EC1? I looked it up in the manual, it was an 8-pin dark-gray connector sitting somewhere between the battery and the relay block. I had to dig for it a little, especially as it was SO tight in there with all the thick harnesses around it.

I finally found it, and what did I see? There were three wires going into the female connector, but NONE coming out the male!!! OMG!!! I had all kinds of thoughts going through my head at this point. Someone had to have just harvested that connector and replaced it with this empty mess. What to do?

Anyhoo, I still did the test. There was continuity from the female connector to the clutch terminal. YAY! It was SUCH a relief to not have to worry about that part of the circuit anymore!

But now at this point, I'm thinking I'll have to just run a tacky little wire from the relay to the connector. Didn't matter if it was just hanging loose in the engine, so long as the AC was working, right? Nah... it wouldn't have felt right :ohcrap: So I decided to look underneath the relay block, anyway, just to see how the wires get connected to stuff from there. What I saw was discouraging. THICK and thouroughly covered harnesses with no room for games. But wait a minute, what was that teenie, TINY little black and white wire I was seeing? Yep, you guessed it. The wire that was supposed to go into the male connector had come loose. I eventually also figured out that the other two wires were actually for the ABS system, with which my car is not equipped, so basically those wires were just open circuits.

But guys, this wire is TINY. It fit in the second smallest space in a crimper I bought. .8mm, or something -- (should translate to 20 gauge but I still feel it was smaller!) There's just NOTHING that small in the vicinity. It could easily have broken when someone tugged at the other harness a little too hard. Or heck, when someone simply moved or changed the battery. I'm not sure what could be the purpose of making this wire so small!

The exposed wire had broken off from an equally
small metal terminal, meaning it couldn't be pried open in order to stick some wire back in. I had to go find this connector, which I discovered only the dealer carries. The guy who helped me had one, that already had a 16 gauge wire connected to it, meaning I'd have to splice it with the tiny wire!! Again, the wire was SO small that it wouldn't even get spliced. It slid right out of the butt connector which I'd already crimped. Went back to the my regular parts store and the guy told me to double the wire over in order to make it thicker and then splice it. Did. Turned on the AC. Worked. :thumbs:

posted by  JaneiR36

eh... apparently, replies to a searched topic do not bump back up to the top. I had to add this post to push it back to the top of the forum...

posted by  JaneiR36

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