GM Malibu heater/air conditioner fan problems

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I have a 1997 GM Malibu LS with 70,000 miles on it. The heater/air conditioner only works at a level 5 on my fan knob. It does work great at a level 5 but at lower levels there is no air coming out of vents.
Any help/suggestions would be appreciated.

posted by  GMWI

you probably have a bad heater resistor. check the repair book in your local parts store for it's location (as i don't have one).

i'm sure someone else here can tell you more about it.

posted by  carls47807

your in luck passanger side floor you can see the fan behind it is the resistor block i just replaced mine before winter

posted by  osborste

I have a 98 Malibu LS with intermittant A/C problems and a separate blower problem. After reading of all of the blower fan problems on the lower settings, I had mine replace yesterday. The problem still remains and I wanted to see if anyone else has the same problem and knows the solution:
1. After working fine, the blower will become very weak with little air coming from vents (there is still a fan noise).
2. When I turn to the highest settings to get some air, there is a deeper, slighter rumbling noise but only slight better flow
3. At times (sometimes independently of the above), the recycle air control will flip to vent air; I can change this repeatedly and often will keep going back.
Since I replaced the blower resistor, are there other things to check?

posted by  terryww

in the other post it sounded like the blower was not working at lower speeds
there are 2 problems here the fresh/recirculate system works off vacuum you may have a bad/leaking switch or vacuum actuator or pinched/broken hose
the blower's loss of air volume could be the ac or heater core has a blanket of dust/lint blocking the flow to clean this you may need to remove the heater box assembly

posted by  osborste

The answer to your problems is ta-da!! the a/c controller contacts are worn.

The a/c controller in your Malibu has graphite contacts which become glazed over time from energy flow and knob adjustment.
When this condition develops, two anomalies occur.
One, the blower motor receiving a weakened signal, generates lower motor speeds and consequently reduced airflow.
Two, the signalling to the a/c clutch can become intermittent and the a/c will revert to vent only and back.

To repair this problem you can do one of two things. Either spend $175.00 for a new a/c controller, or remove the controller and repair it.

The repair is relatively simple and takes less than an hour. The a/c controller housing is a snap together design that with a little care can be opened without breaking. First, remove its knobs to facilitate its opening
Once open, you will see two sets of grapite trace on the PCB board. The glaze on these traces from the metal glides should be evident. You need to remove the glaze and restore the graphite surface.
To remove the glaze use a pencil eraser. Follow the trace in a lengthwise sweeping motion. Do this for each of the four traces. If the glaze is still deep, use a hobby sanding stick with a fine sandpaper, sanding in a lengthwise motion. Next, put rubbing alcohol on a cotton swab and clean the contacts of debris and of the acid left from the pencil eraser.
Now that the contacts are glaze free (or pretty close) take a #2 pencil and draw over the traces lengthwise. Cover the traces with a thin layer of pencil graphite. You can lightly swab the traces if you see any new debris.
Place the controller buttons back into their positions (They probably fell out) and reconnect the two halves of the controller body. Re-install and enjoy cool a/c again.:thumbs:

posted by  b.b.wolf

I'm sure that person left sometime ago since this thread is almost a year old.

posted by  Benson

B. b. Wolf is right on. Thank you. :clap: :clap: You saved me $175, and the fix was so easy to do, only took 30 minutes.

Any one experiencing this problem can do the steps outlined from b. b. wolf and fix it themselves.

My experience was this: My fan worked great. I only experinced the A/C switching from Recirc to vent on a consistant basis.

Hope this helps someone out.

posted by  TekEAndy

Amazing what search will do - Mr Wolf hasn't been back since his post in 2006.

posted by  tbaxleyjr

Amazing what reviving dead threads will do. I have the same problem on my Alero (fan only works on high), knowing GM, they put the same cheap piece in 3/4 of cars. I've been putting that and the defroster anomoly off for that car, maybe I'll be able to kill two birds with one stone tomorrow.

posted by  giant016

yeah, I think my dad replaced the knob on his '98 Venture last year for the same reason...

posted by  dvdrose18

Most manufacturers have some commonality with parts between models - lowers manufacturing costs

posted by  tbaxleyjr

Very true, I think I just thought of GM in particular because they have so many different models in the US compared to say Honda or Toyota.

posted by  giant016

I think it has more to do with trying to save a buck for GM, seems to happen more and more these days, I suffer from the fan problem and know 4 other people with the same thing, 3 are malibu's and the other is also an alero, these cars were all built pretty much off the same platform with just a few different cosmetic tweaks etc.

I also have a voltage problem where all lights dim if you touch the brake or turn on the rear defrost, it even will dim and brighten when idling, my battery is awesome and have never boosted.

There is also a vibration occuring at around 120km, it gets noticeable when you turn the wheel slightly, bearings are good and have replaced one tie rod and gotten an alignment, although I am in need of some new tires since the outside drivers side is almost completely bald.

posted by  cowman85

IIRC Honda uses the same platforms as Lexus, Nissans use platforms from Infinities, etc. It doesn't make sense financially to design a platform that is nearly identical to another one.

That being said it seems like most late 90's to early 00's GMs are problem-ridden. Aside from teh ALL MIGHTY LS1 of course. :laughing:

posted by  giant016

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