1999 Riviera A/C Vents

A friend has a 1999 Riviera. The air is cold coming from the higher vents on dash but the lower vents and vents on each door give hot air even when the air is on. Wasn't always like this but recently started. Are the vents controlled by vacume or 12v? Is there 2 separate vent control systems on this vehicle? Any help at all would be appreciated. Thanks

sounds like an actuator is stuck. it may eventualy fix itself if you play with the temp controls long enough or the ambient temp changes ,etc. tho usualy the controls control pass/driver vents not upper /lower so it could be something else.

I have problems with my vents on my '96. Cold air on the right, warm air on the left and center vents....Is there any way to get the the actuator if that is the problem? Could it be a low freon charge?

Thanks.

more freon will not fix that. you need to take apart the driver side panel where the HVAC stuff is and find which mechanism controls the hot/cold flow to the driver and center vents. that's the one that is defective and stuck half way. replace the part or "rig" it and your set.

HVAC? Under the column?

Be aware that a bad ac compressor can cause this problem
My 1996 had cold air coming out only on passenger's side, the rest of the car was vent air. Thats up until I replaced the AC compressor

My 1995 Riviera has just started to demonstrate a similar malfunction.
The vents on the passenger side blow hot air but the vents on the driver side blow cold air.
I am not mechanically inclined and do not wish to invest a large amount of money in a 1995 vehicle. What would be a reasonable cost for a local garage to correct this situation assuming it is not the compresser but a stuck valve (actuator)?

My 1995 Riviera has just started to demonstrate a similar malfunction.
The vents on the passenger side blow hot air but the vents on the driver side blow cold air.
I am not mechanically inclined and do not wish to invest a large amount of money in a 1995 vehicle. What would be a reasonable cost for a local garage to correct this situation assuming it is not the compresser but a stuck valve (actuator)?


dont let local garage determine the situation. find out what exactly is wrong yourself.... people here will help you. then go to garage to fix the specific issue. You know how some mechanics do.

Possibilities for cold air on one side vented on the other:

Actuator (listen if it moves the air passageways)
Low freon
Bad compressor
cloged passageways (depending on situation)

PS. maybe there are other reasons, but im not a mechanic and speak from personal experience/forum knowlege

take the glovebox out and see if the 'controller' is there. This is where the blend doors and acutators are mounted. Even if its vacuum and not computer controlled, you need to see what those are doing. It sounds like a blend door or the blend door actuator isnt functioning, but if you can move from dash to vents to floor, i wouldnt blame vacuum supply.

If you're notorious for putting crap on your dash, I've seen pens/pencils/'stuff' in there.

I wasted a lot of time going to Pep Boys, my regular mechanic (who replaced the actuator), and my own neck-twisting labor when this happened to my wife's 98 Riv. We all assumed the a/c was working, as it was blowing cold from the center vents. (This was during our 106 degree Texas summer).
Eventually took it to the dealership, who diagnosed a cracked compressor and topped it up with Freon, as I wasn't about to pay several hundred for a new compressor. It now works fine, and has done so for about 3 months. Must be a preeeetty slow leak!
So, bottom line - start by getting the Freon topped up before spending a lot of time dismantling the ducting!