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Old 08-07-2004, 04:16 PM   #46
DodgeRida67
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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!)

Last edited by DodgeRida67 : 08-07-2004 at 04:19 PM.
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Old 08-07-2004, 05:52 PM   #47
JaneiR36
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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!

Last edited by JaneiR36 : 08-07-2004 at 06:00 PM.
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Old 08-08-2004, 02:32 AM   #48
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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.
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Old 08-08-2004, 03:27 AM   #49
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Quote:
Originally Posted by DodgeRida67
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.

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
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Old 08-08-2004, 03:32 AM   #50
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Quote:
Originally Posted by kanato
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
It doesn't work quite like that.
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Old 08-08-2004, 03:46 AM   #51
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Quote:
Originally Posted by DodgeRida67
It doesn't work quite like that.

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.
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Old 08-08-2004, 06:48 AM   #52
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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?
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Old 08-08-2004, 06:39 PM   #53
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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.
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Old 08-08-2004, 06:48 PM   #54
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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.
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Old 08-08-2004, 06:58 PM   #55
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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.
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Old 08-08-2004, 07:01 PM   #56
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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
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Old 08-10-2004, 07:31 AM   #57
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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.

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Old 08-10-2004, 07:57 PM   #58
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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. Maybe the relay was bad, but it wasn't the only thing that was bad.
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Old 08-10-2004, 11:04 PM   #59
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ALRIGHT! OKAY! I'll give you sense!!! (Homer Simpson style... he he ). Actually, I've got some pretty interesting readings now (how many readings does it take to measure one damn relay, you say? ). 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 Actually, please, oh, please tell me anything that could be wrong! I'm so damn close to fixing this!!!
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Old 08-11-2004, 01:08 AM   #60
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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.
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