A/C not working right

Aside for checking the system for fault codes, I would suspect a faulty blend door actuator, or faulty expansion device. You can try disconnecting the battery cables and touching them together for a minute or two. reconnect and see if the behavior changes.

Yesterday monring the battery in my 2004 Tahoe was dead. After replacing the battery, the motor idled a little bit rough for a few seconds, but then normalized. However, my air conditioning will now only blow out of the defrost vents. This is the case regardless of whether the system is set on "auto" or whether you manually select the vents (i.e. dash vents, floor vents, defrost, etc). Prior to the battery going dead, I had no problems with the AC. Just because of the timing, I assume the dead battery and this AC problem are somehow connected. Can you offer any advice on possible causes and solutions?

The mode doors are operated by a small electric motor/actuator. When the battery is disconnected and reconnected, many of them go through a calibration sequence to determine the full range. Quite often the door will get jammed at one end. If you look up under the dash from the driver's side, you should be able to see the mode linkage and you may be able to help it along.

What does the mode linkage look like? Not exactly sure what I am looking for. Does it have a white plastic half circle shaped gear on the outside of it?

Yes, that's it. It operates more than one door by moving levers when it rotates.

Had the compressor replaced in Aug 07. AC worked just fine until May 08. Starting blowing out warm air with an old AC smell. In mid May I had the 'head' (part that is in the dashboard) replaced. It worked for two weeks - not great but it put out cold air, then a minute or two of warm air w/ the smell again. Yesterday it stopped putting out cold air completely.

These parts are 1 year warrany parts..but I would make the shop that did the work fix it for ZERO....there may be a leak, or an electrical problem

That did the trick. Thanks very much!

Glad to hear that.

Leaving positive feedback would be appreciated.

I have a 2003 Chev Tahoe z71 with 88,000 miles. My Air Conditioner cools fine and then it will blow warm air for awhile. It will then start to blow cold again. Once or twice I have noticed smoke blowing out of the vent for a few seconds.

You should have it checked by a certified AC repairman.You could have excessive moisture in the system in which case the receiver dryer needs to be changed or it could be a malfunctioning pressure switch or thermostatic switch at the evaporator.

Just had another(2nd tine in a year) New compressor put in (1st one took 11 years to go out ), cold blows in front. Nothing happening in back. No air, no sounds NOTHING. Have gone back and forth with my mechanic and need to get it fixed Live in Az and my family is HOT sitting in the back. Does a certain button need to be on. Trust me I have checked all but get nothing no matter what button I turn on any level.

You have an electrical issue with the rear unit that needs to be diagnosed. Could be fuses, either of the switches, the resister, the wiring or the blower motor itself. Someone is going to have to test while following a wiring diagram.

i have an 2000 chevy tahoe limited old body style 2w drive, 5.7 liter. it has front and rear a/c but olny the rear blows cold air and the front only blow hot when a'c is on. even after the a/c was recharged. what could be the problem"

That could be a plugged orifice tube or a problem with the temp blend door. If the pipe coming out of the evaporator is cold, then it's likely a blend door problem, probably an actuator.

I recently purchased a 99 Tahoe which is in pristine condition, however on my way to work a few days ago the air conditioning was blowing ice cold then slowly faded away to just air. I turned the ac switch off and proceeded to work with the windows down. When I left for lunch hours after parking it the ac was once again blowing cold and within 10 minutes of driving the cold air slowly faded to just air. When I got home I opened the hood and noticed the compressor was not engaged even though the switch was on and on Max / Hi. So I know that after you let the vehicle sit for hours on end the ac will work for 10 minutes or so then quit blowing cold air. Could this be the ac control switch on the dash? I noticed when I turn the blower switch to the off position the light on the ac button itself flickers and if I wiggle the switch around the lights flash as if their is a short.

The AC control heads are notorious for going out. Various lights flickering is a symptom to look at for that problem and this could cause the compressor not to engage. Another thing that could be the cause is the low pressure switch mounted on the accumulator. With the ac on and the compressor not running, lightly tap the switch with a wrench of something, just not too hard....OR unplug the switch and take a jumper wire or a pair of needle nose pliers and jumper across the 2 terminals of the switch connector. If the compressor comes on with the switch connector jumpered, then either the switch is defective OR the refrigerant system is low on freon. Either way if the compressor comes on it rules out the control head being the cause of the compressor not engaging.

I changed my compressor and the front ac was work but not the rear so i changed the orifice tube and the rear regulator valve and now the rear works but not the front i used 3 12oz Is this enought if not how many cans do i need to fill the system.

I tshold tell you on the truck there should be a sticker underhood with charge amount. 2.71 lbs.all models. or 44 oz.