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Q: front ac blows hot air rear blows cold on 2000 GMC Yukon Denali

just recently my denali started blowing hot air out of the front vents,while the rear was still blowing cold air. Is there an easy fix for this?
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On all yukons or tahoes or suburbans thay all have two ac systems... the back system has two boxes on it the very first one is the one u need to replace... it controls the system to open and close the heat port on the system... if it is closed it will only blow cold if it is open it will only blow hot... you can take that off and manually open it but when summer rolls around youll have to do it again and close it... will post a link from youtube later that shows exactly what im talking about... hope this helps

Okay guys here the link to what im talking about.
I wish I had the answer I have a 1999 Yukon Denali and the exact thing is happening to me. Warm in front, cool in back. Please post any answers as I would like to know as well.
a/c is working fine. sounds like the diverter door is remaining open allowing the fan to blow air through the heater core. this door is often controlled by engine vac or and electric door motor closing device. A good mech at the dealer should have found this.
bye now bob
very interesting, i have 2003 gmc yukon denali. The passenger side started blowing warm air. Drivers side and rear air all blow cold. Have you found any answers???
I have a 2004 GMC Yukon XL that the front blows cool air then it gets hot and goes back. The back air is working great, but it is a separate unit. The dealer recharged the system 2 weeks ago for $140 and now it is back today because it just isn't right. It has to have something to to with the compressor kicking in or a relay. I still have an extended warranty on it and they need to figure out why this is happening so it can be covered and repaired or replaced.
I am having same problem. Not the fan motor cause we replaced it, not circuit board cause we replace it. Please let me know what works for you before I get rid of this thing.
I also have this problem. I asked the dealership about it, and they wanted a $70 diagnostic fee to look at it. They said they $70 would be credited to me on the repair bill if I decided to have them fix it. But, I don't wanna pay for them to guess if they cant find out for sure. Will anyone's dealer give them a free look/ advice?
the door that moves from heater core to ac evap is either broke or the motor is not working properly. Very rarley does the orfice stop up on the front ac. Feel to th back of the dryer and see if it is cold or if you can see condensasition dripping on the ground up front behind the right front tire. If it is cold or the dryer/accumulater is cold , it is the door or motor problem
I recently worked on an 05 Tahoe with a similar problem. Maybe the same problem. It was cold out and the heat would not work in the front only. Turned out that the blend door motor was dead. It is under the glove box at the passengers feet. A small servo motor that turns hot and cold air valve in the heater box. I pulled the small flat motor off and noticed the shaft was jammed and would not turn when i moved the temperature selector knob from hot to cold. I reached in and turned the air valve with my finger and verified that it was not stuck. Customer replaced the motor himself and everything is working now.
I have a Buick Lesabre that blows cold on the passenger side, and hot on the drivers side.

I would like to follow this question it may be related to my Buick issue
My 04 silverado starts off cold on both sides then sometimes the driver side vents will blow hot air. when we stop and turn off truck and start it up and it is fine again. Could it be the thermostat for that side not working??? anyone have any answers for this problem?
did you ever find out what was going on with your silverado cause i have the exact same problem with yukon.
i have the sma problem with a 2007 chryler aspen bought it 2 months ago all they said was sorry at the dealer you have drive train warranty but not for that bought it in the summer so didint try heater when i bought it screwed now
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