Unusual AC problem, half hot half cold

The AC vents on the dash blow out cold air on the passenger side vents (plus one of the center vents) and warm air on the driver's side. I can't imagine how this can be. Our long time mechanic looked at it and said he can't figure it out and to take it to a dealer. I was wondering if anyone else ever had this problem or heard of this problem.

I will say that we recently had a new valve installed because the rear air quit working. The rear air is fine. It was only after the rear air was fixed that this problem with the front air occured. It could possibly be related or it could just be a coincidence.

Sound like one of the HVAC door servos might be failing. The HVAC internally is comprised of compartments which are divided by doors. These doors are controlled electronically by the temperature and mode switches on the dash. The doors are responsible for cold and hot air ratios to adjust to the desired temperature whether it be cold or hot or in between.

You didn't mention what year your van is, but I believe the later models (2000+) have electric motors (or servos as mentioned in the previous response) that control the temperature doors on each side. That is - there is one for the right side and one for the left side.

I had a similar problem with the defroster on my 2001 Venture (see http://www.my-chevy-venture.com/venture-defroster-problems.html )
and while I was in there I saw the two separate motors on each side.

One of the motors could be getting weak, there could be something inside the system that is causing the doors to jam, or even a loose wire at one of the connectors.

If you take off the insulator panels you should be able to get a look down there and see what's happening.

Good Luck,

The van is a 2001 Olds minivan. Last fall the darn thing started working again, we will see if it is working this spring/summer. If not I will know where to look.

Ironically, my Jeep had a problem with the HVAC door that you guys are describing. I had a new condensor core put in and when the mechanic reinstalled my dash he bound up that door causing me to have full AC all the time. I couldn't regulate the temp. In fact I could get no heat at all. The dash had to come back out so he could reinstall it properly.

Thanks for the replies.

Good Morning! I had a simular problem with my 97 olds.It turned out to be low refridgerant.You can buy a gauge at any auto parts store,Hook it up to the low side refridgerant port,start engine and turn a/c to max position.You will get a good reading if the outside temp is above 65-70F.My a/c was blowing cold at the rear a/c,And luke warm at the front a/c (dash panel).One can of refridgerant fixed the problem! cost(With gauge) was about $25.00. Have a good day! Keep Cool!! Diesel1962...

I have the exact problem, I have cold air in the passenger side of the van,and warm on the drivers side. Has anyone found a fix for this. Any help would be great. I have taken the dash apart and can'f find anythingto replace everything is stuck inside the AC box behind the radio.

mhm

diesel62 was right. My mechanic suspected the servos doors but before he would mess with those he added a can of refrigerant. That solved the problem.

Sound like one of the HVAC door servos might be failing. The HVAC internally is comprised of compartments which are divided by doors. These doors are controlled electronically by the temperature and mode switches on the dash. The doors are responsible for cold and hot air ratios to adjust to the desired temperature whether it be cold or hot or in between.
I have the same problem as you guys! I have the van all apart and still cant figure it out. Have a full charge on the system. Haynes manual opened to the proper section with no help. Check the fuses. Checked the vaccum lines. Checked if there was anything getting in the way. A/C blows 15 degrees cooler on the passenger side and in the back. Wife is really starting to complain with the temp gettin into the 90's! PLEASE HELP! Thanks!

The Ventures,Siloutte and Montana mininvans do have problems with the a/c condensors,the lower right mount breaks off.Most places that sell the a/c condensors stock them and an updated j clip has be purchased at the dealer.If the new a/c condensor fails,only way to warrenty it is if the updated j clip is installed.The is a tsb on this.

How would the condensor having a broken bracket cause one side of the dash to blow warm? I'm not following that one.

There are multiple parts to the AC system. When you recharge with the 134A you have a certain amount of OIL in the system. Sometimes you can have a full charge and still not have cool air everywhere because there is to much OIL/ Debris in the system. An AC guy can fix this easily by evacuating the oil and debris out of the system. If you notice cooler air at higher speeds this is also the same problem.