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Chevy Suburban and Tahoe AC and Heater Problems



  • alawinalawin Posts: 6
    I have a 2001 suburban. The ac switch seems to work, light comes on when depressed, goes off when pushed. However, the compressor seems to run all of the time regardless of the switch setting. Any ideas? is this normal. I do not have the vent controller set on defrost.

  • kiawahkiawah Posts: 3,666
    Had a 97 sub (replaced now with an 07), so can help a little.

    In regards to (2), the rear unit has it's own set of circuitry, blower, ductwork and sensors. You can find it along the right rear. The bulk of it is in the far back, but ductwork and sensor runs all the way up to the 2nd door on the right. Access it from the far back.

    I still have my factory service manuals, so can look up something for you if you have a specific question.
  • kiawahkiawah Posts: 3,666
    There is a set of high and low freon pressure switches, which control relays, which controls the operations of the a/c compressor clutch.
  • alawinalawin Posts: 6
    Thanks for the response. However, I fiddled around some more and found something interesting. The compressor stays on continually (regardless of ac switch position) only when I have the recirculate air selected. The ac switch functions normally when I have the fresh air selected.
  • alawinalawin Posts: 6
    I can hear a click when I hit the window button from either the driver's door or the affected door. I would normally think this was a motor that needs to be replaced. However, there was a brief period when the window started working, it functioned normally for about two weeks then quit never to work again. I can still here it picking the motor when the switch is depressed. I dont want to waste the money on a motor if I have a short. Any ideas? thanks.
  • hand3hand3 Posts: 1
    I have a 2002 5.3 liter tahoe. For the past year the rear a/c, heater, and blower ... for no reason will stop working. Then later on ... after the vehicle has been parked and resterted ... the overhead selector switches, for the rear a/c, would begin operating the system again. Then after a few more months, only the front overhead a/c controls would operate the rear a/c, heat, and blower. But as I said earilier, for no apparent reason, the rear blower would stop blowing. Now nether the front or rear, overhead controls will operate the rear a/c, heat. or fan. it's hard to believe that both switch panels are defective. The front passenger a/c, heat, and blower works fine. Any help would be appreciated.
  • jweast99jweast99 Posts: 1
    I have a 2001 Suburban. The air conditioner works fine, unless the car is wet (after rain or car wash) the light on the dashboard won't light and the A/C won't work. This happens whether the car is idling or moving. Once the vehicle dries off the A/C starts working again. Not sure what is causing this. Any ideas?
  • camocavcamocav Posts: 7
    It seems when I'm stopped at a light, sign, or wherever, but in gear, I get a load vibration under/behind the firewall. A GMC deal informed me of a Tech bulletin as the HVAC/exhaust was part of the problem, but a $130.00 for clamps and $80.00 for labor(my GM extended warranty wouldn't cover it either). would do the trick. I checked the exhaust system and it was NOT vibrating, so that was out. As fo the HVAC, ?? So, I read a post by Arrie on adding a can of oil treatment to their Tahoe's AC system due to compressor noise. I'll see how it works, hopeffully it does as the vibration is load at times. Anyone else have issues like this?? :confuse:
  • 96gmcburb96gmcburb Posts: 2
    Well yeah would you look up what the parts are called?

    i know blower , but there is a black electrical box that seems to be the area the ticking is coming from it is in the back up and towards the third seat under the side cover .....what is it called?

    Thank you ,

  • kiawahkiawah Posts: 3,666
    Well I'm looking in the manual, and I don't see the break out of it, but I know it's here in this manual somewhere....since I had to get into it a couple of times when I owned it. Here's what I remember, so this is all from memory..

    There is the blower motor, with a resistor bank in that housing, which is what drops the blower speed to lower voltages and slower blower output. The resistor bank is cooled by the air flowing thru the blower motor. There are a couple of relays, which switch the resistor in and out, slowing the speed. Further up, as I recall about half way, is a plenum mixing door which is basically adjusting the temperature by adjusiting how much air goes across the heater/ac coils. Also as I recall, all the way up in the plenum output by the 2nd seat door, is a sensor which is what it determines to monitor the output temperature of the air.

    I had a situation once where the blower was running all the time, turns out it had a bad relay (in the back controlling the blower motor). That was replaced by the dealer under warranty, I don't remember if there was a TSB on it or not.

    If you hear clicking back there, it is most likely the relay controls.
  • dwalton1dwalton1 Posts: 1
    rear air not working at all front works great .I checked fuses under hood and dash .Just need some help
  • calipagcalipag Posts: 1
    I am having the same problem, did you ever figure out what was wrong?

  • domabrosdomabros Posts: 1
    Front air is ice cold on my 99 suburban,rear air not.Vent door selectors are both working in rear,one for heat or a\c,one for floor or ceiling.Any suggestions?
  • nflguynflguy Posts: 90
    I have a 2007 tahoe LT3 that I bought in October 2007.

    In Dec 2007 the readout on the dash (where you can view the odometer or the tire pressure etc) went haywire. Instead of the usual stuff it displayed some random numbers and was stuck on that screen. 20 minutes later it suddenly started working fine. I brought to dealership and they said nothing was wrong.

    My XM radio will go out briefly now and then and I don't live anywehere near tunnels, mountains etc. I could be in the middle of a parkinglot and suddenly lose reception. This is weird becuase XM is sattelite.

    Now for the bigger issue:

    Around March I noticed that the blower speed seemed to fluctuate without me touching a thing. I would set the fan speed to a middle setting and then while driving it would go up and down. I called the dealer and they told me to turn on the max air/recirulator button that would fix the problem.

    It didn't fix the problem so i dropped my tahoe off at the dealer. They kept it overnight and told me everything was fine. They said that if the fan speed was having problems there would be a code and they didn't find any codes...

    Now it's late June, 2008

    My fan speed fluctuates wildly while driving(i never use the auto function).

    The Max air/air recirculator button will turn off on it's own!!!!

    I called another dealership and they said it could be a problem with a blower resistor or the control head BUT the only way they can replace those items is if the onboard computer shows codes indicating those items need to be replaced.

    ANY help ior suggestions would be greatly appreciated.

    You can also email me at
  • natalenatale Posts: 5
    I have a 2002 Chevy Tahoe that when you put the ac or the heat on and step on the gas you hear this really lound like clicking noise. You let off the gas and the truck idle and there is no noise. The air comes out cold as ice and the heat works great as well. I had a mechanic look at it and he suggested changing the tensioner and the belt or it might be the compressor. I changed the tensioner and belt and the problem still remains. Does it sound like the compressor? Has anyone else had this same problem? Mechanic stated it will cost $500.00 to replace? Does this sound correct?
  • I have a 2002 Suburban and I have the same exact problem and i have done the same things so far as replacing the tensioner and the belt, and it is still doing the same thing, I want to know how long i can drive and how far I can drive my suburban like this.
  • natalenatale Posts: 5
    When i took it in to the dealer tha ti bought it from for this problem (Not a chevy dealer) they said it would not hurt the vehicle. I am ultimately going to bring it into chevy to have them take a look at it and diagnose it. I dont honestly think it is the compressor because they said it is gumming up because of the freon. So my answer then is ok, then what about when i turn on the heat? Their is no freon being used when you run the heat. They also told me they received a memo from GM on this problem. I just hope it is not going to cost $500.00 or more to replace. This is the first problem i have had with this vehicle in the three years i have owned it. On top of the cost of gas now unfortunately i have to worry about this. I have found tha twhen driving after you get going you can turn the air on and the truck will not make the nosie, unfortunately after you stop for a light or to turn you need to shut off the air so that when you step on the gas the truck will not make the noise. Let me know if you find out any additional info and i will do the same.
  • jerryingajerryinga Posts: 1
    the problem could be the radiator fan clutch. while driving there is enough air blowing across a/c condenser and radiator. when you stop if the fan clutch is defective, there is not sufficent air flowing to cool freon in condenser coil.
  • arriearrie Posts: 312

    I understand that you have found out that the noise comes from the AC compressor? So, if you turn the whole heating / cooling system OFF you do not hear it? In some cars, like in my '04 Tahoe, AC compressor runs almost always regardless if you are heating or cooling. Even in heating mode some systems use AC compressor to dry the air so your windows do not fog over. That is why compressor typically runs if you select the wind shield operation.

    If the noise really comes from the compressor, like I believe it does based on what you say, there is one very simple and inexpensive thing to do to see if it helps. Go to any auto part store and buy a can of oil charge for the AC system. Your car is 6 years old and possibly has never had this done.

    Just like in any oil lubricated system the oil loses its lubricating properties over time and this can lead to wear and ultimately burning of your AC compressor.

    To charge your AC system requires a charging hose, which should not cost more than $10. Anyway, the can of oil charge and the hose will cost less than $20. If you don't have a handy man at home to do the job I would think someone at parts store might do the job for you but you will need to buy the can and the hose.

    The job is very easy and you probably can do it yourself too. You first make sure the needle valve on the charging hose is turned all the way open. This ensures the needle on the valve does not pierce the can when you screw the can in the valve.

    Then you unscrew the plastic cap from the low pressure service port in the cars AC system. This is the port right close the AC dryer canister (aluminum bottle at passenger side on fire wall). This line is also the one that is cool to touch (when AC system is running). When feeling the line do it next to the service port because the same line is HOT if you touch it on high pressure side of the expansion valve. In my car the expansion valve is just about 10 inches before the service port in this same line so the same line has hot and cold parts to it.

    You will connect the charging hose to the low pressure service port (the fitting on the hose will not fit in the other ports if you have purchased correct charging hose) while the engine is running on idle with AC on max cooling.

    Then holding the can upside down you will turn the needle valve on the charging hose to full closed. This will pierce the can. After this you open the valve holding it upside down and the ac system will suck the contents in the system. You will need to shake the can before you do all this and they instruct to shake it while it is flowing in too. It only takes about 30 seconds for the oil charge to flow in the system.

    If oil charge gets rid of the noise you should be fine as you say the air coming out of the vents is ice cold.

    If oil charge does not help at all you might have a bearing problem with the compressor.

    Bearing problem can be such that when you accelerate the extra force from acceleration can cause the bearing to make noise but when you drive constant speed or do just moderate acceleration during driving noise is not generated as acceleration force is not big enough to cause problem.

    If it is bearing issue you could try lubricating the bearing but it is very difficult to do and probably requires removal of the clutch and pulley that turns the compressor.

    $500 is not bad for AC compressor change as just the part for my car costs almost that. I guess the mechanic was talking about the cost for the compressor, not it installed. For the job you need to re-charge the system and to do that correctly the system must be vacuumed first after compressor change. And if you are to have compressor changed you probably want to replace expansion valve and the AC dryer canister too. At least that is what I would do if I had to replace my compressor.

    With all this work and parts you might be looking a bill around $800 instead of $500 so please do yourself a favor. Try the oil charge first as if the compressor is just running little dry it might save you that $800!

  • esther08esther08 Posts: 3
    The rear air doesn't work on my '02 tahoe. I checked the fuses in the box but couldn't find any that where blown, any ideas?
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