Partial AC Failure

[spooltime]

Today, with the AC controls set on "Auto" and the temperature on both the driver's side and passenger's side set at 73 degrees, I noted that the driver's sides vents were blowing nice cold air as expected given the outdoor temperature, but the passenger side vents were blowing nice, WARM air. Obviously, there is AC available, it's just not getting to the passenger side. I'm thinking there must be a valve or something under the dash that has failed, but before I take it in for service, can anyone suggest potential causes based on the symptom? I plead ignorance for the most part on HVAC-related stuff. I'd like to point the service writer in the right direction if possible.

[hahnmgh63]

Can you run a Durametric Scan? Their are multiple little motors/servos that direct Vent air, and they are known for fail. The Fresh Air Vent Servo (causes fogging windows in Econ mode) is the only one that is relatively easy to get at the others require a fair amount of panel removal. Their are 3 I believe on the drivers side of the HVAC system (above the drivers footwell) that are commonly known to fail (I have a fault showing in one of mine now but no adverse affects noted yet so I haven't dived into it).

[mcbit500]

Try switching to MONO and see if you get the same end result.

[wilsonkuo]

Hi there,

I am new to the forum.

How to switch to MONO?

I have a similar problem as my Passenger side middle vents are blowing cold air while I have both side set to be hi/hot.

I don't have duramatric scan ability if it is actually a scan tool.

Thank you and blessings~

[clarksongli]

Hold the Auto button an then it will display MONO on the HVAC sceen.

But whether it's mono or not, the same servo controls the warm/cold mix.....it is possible the control sign is bad, but 99.99% of the time, it means one of the servos stuck or failed.

[mcbit500]

But whether it's mono or not, the same servo controls the warm/cold mix.....it is possible the control sign is bad, but 99.99% of the time, it means one of the servos stuck or failed.

Absolutely, but its just another step in the process of elimination.

[wvicary]

If the A/C system is low on freon it will exhibit this fault.