HVAC mixing valve issues
 

In my 2004 CTT, the passenger side vents put out warm air no matter what the HVAC controls are set to do. The driver side blows much colder air. That includes the middle pair of vents blowing different temperatures. I suspect that the entire climate control system would work more efficiently if it were not heating half the car and cooling the other half in its attempt to maintain temperature.

I have read that there are mixing valves that sometimes go bad. I don't have a Durametric but could maybe get to someone who does to find out if there are any codes in the HVAC system. But one thing I can't find is part numbers or diagrams to figure out where the valves are, how expensive they are, and how to replace them if I do identify which one needs it. All I have found is people saying that it can be done.

Does anyone have some tips on this? Thanks.

I recharged the A/C R-134a a bit last night. Now both sides blow cold air. I don't know why the driver side would work better than the passenger side if the refrigerant is low, but I won't complain about this apparently fixing the problem either.

you should probably have an ac shop test for r134 leak using a sniffer.

otherwise, you can be charging every summer

That'll be the next step, when I'm in a town with an A/C shop and have some time. For now, I'm just glad that I don't have to abuse my hands trying to replace mixing valves.