Air suddenly hot from the passenger side

theophile

Well-Known LVC Member
Joined
Apr 30, 2013
Messages
223
Reaction score
12
Location
Jackson
'02 V8 Sport. I know this topic has been done to death. I replaced the DCCV with OEM 2 years ago. Last year I replaced all plastic cooling parts and upgraded to the aluminum Jag t-stat housing. Over the summer, my A/C compressor seized up and I had a reputable shop replace that, along with the system components you have to pull the dash to reach. But other than that, everything's been fine in terms of the HVAC system operation.

Then about a week ago, we got the first cold snap, and that morning on the way to work, the air coming out the passenger side was hot. I ran the HVAC self test, which completed as I was pulling into work. On the way home, and for the next few days, everything was fine again. Then yesterday morning, the same thing, except the self-test didn't fix it, nor was it working properly again on the way home. The HVAC system is throwing no codes.

My initial reaction is that it's something electronic, as the issue just happened to occur on the first cold(er) morning of the season. I've also been having some other odd electrical gremlins, such as the horn sometimes not chirping to confirm the doors have been locked, or the steering wheel sometimes not returning to the previous configuration, and the wipers often behaving in a manner inconsistent with the setting they're actually on. I replaced the FEM with a used (but supposedly tested) one a couple years ago due to a power steering problem, and I wondered whether this "new" one could also be going bad. But it looks like the FEM isn't involved in the HVAC system?

Anyway, I'd be grateful for comments/suggestions for pinpointing this annoying issue.
 
If the self test has no faults, then it's either a mechanical failure of the DCCV, of a failure of the passenger side air discharge temperature sensor. You can unplug the sensor and see if the behavior changes. I think you would then get mostly or completely cold air out of the passenger side, if the temperature sensor is the problem.
 

Members online

Back
Top