A/C is acting up.

Question

The air conditioning in my 07 Impala has been acting up. Usually when I first start the car I turn on the ac and after some time it gets cold like it should. However I noticed after leaving it on for a while the air becomes warm like around 72F (checked with temperature gun). I honestly don't really know what's causing this, especially the second I go to brake and turn onto my street and the ac starts blowing cold freezing air out of nowhere. I tried asking someone I know and they potentially think it's the HVAC Computer module acting up, I'm honestly not sure at this point. What I've done so far is check the refrigerant which is perfect and checked the cabin air filter which isn't super dirty and not clogged.

Chuck Tobias · Answer

[quote data-userid="180198553" data-postid="314792"] What I've done so far is check the refrigerant which is perfect [/quote] How did you check it? It's not really possible to know the refrigerant level unless you pull the refrigerant into a recovery machine which will weigh it. With a variable-displacement compressor you can't really judge the refrigerant level via pressures. There are many things that can cause warm air from the air conditioner. It's all computer controlled and diagnosis of the electronics requires a dealer-level scan tool that can do bidirectional testing. You could also do some basic troubleshooting via component temperatures and operating pressures. Make sure all radiator and condenser fans are operating, compressor clutch is engaging, and the condenser has sufficient airflow (not clogged with debris, fins are open). However if you're not familiar with working on air conditioning it would be best to take the car to a good independent HVAC technician. It's very easy to do more damage or even injure yourself. https://www.youtube.com/watch?v=3JrqdppVmcU https://www.youtube.com/watch?v=_Qt6UCmzRH4 https://www.sanden.com/objects/SANDEN_SYSTEM_DIAGNOSIS_CHART.pdf