Problem: AC stops working randomly on long road trips in hot climates

[OilGuy]

I'm puzzled, but it's happened to me a couple times now in my '08. Cruising along as normal with the Auto-controlled AC on in the middle of a long road trip in hot weather (~90+F) - we notice that it suddenly feels warm after being quite comfortable for miles. We check the climate control system and the settings appear normal: Auto on, target temp is low, fan level is normal. We manually crank the temp setting to minimum 64 and max out the fan. Hardly any air comes out of the vents at all - it is barely trickling, and it's not cold at all - but you hear the fan noise. Cabin air filter is not clogged and things were working fine minutes before - the system just stopped working. Additionally, the center console plastic where the front passenger can rest their left leg is quite unusually hot to the touch - you do not want to rest your leg against it - something is really hot beneath it.

We turn the system off and crack the windows as the next best option to try to minimize sweating for the rest of the trip. A ~hour later I try the AC again and things work fine.

Any ideas on what is going on?

 

[rodslinger]

Sounds like the evaporator is freezing up. Usually caused by restricted airflow or low refridgerant charge. Might also be the evap temp sensor came loose and not reading evap temp properly either.

Pull the cabin filter and check it first.

 

[OilGuy]

Check the cabin air filter for what - being clogged with debris? If so, I did replace it - there was some debris, but not a lot - a majority of the surface area was open. Perhaps even a little surface area restriction is enough to make an impact?

Thanks for the insight!

 

[rodslinger]

Since the filter is new the next likely item is the evap temp sensor mounted on the surface of the evaporator has either gone bad or came loose and not reading the evap temp at all. Gotta get to the evaporator to physically inspect this one. Don't have the FSM to tell you how to get to it.

 

[OilGuy]

Thank you!