Scotty, is it a bad thing if I turn off my car if the A/C is still on, or should it be fine?
That's a good question. I was always told to turn off the A/C before turning off the car...but it may just be an old-school saying. I don't see how it's bad for the engine and/or compressor. I'd like to see what other people think about it.
If you live in a humid area, a cold A/C evaporator will attract condensation. When the car is shut off, there is no airflow, and over time the wet evaporator could get mildew and start to stink.
In this situation it can help turn turn off the A/C, but leave the blower on when you're 10 mins from your destination. This will dry off the evaporator.
Some GM vehicles have a feature that the dealer can turn on called after-blow. This allows the blower fan to continue to run on a timer after the vehicle is shut off.
On really old cars it was a good idea to get into the habit of turning the AC off so it would not be an additional drag on the starter when starting the engine. I have a 50-year-old station wagon that's like that, the AC system uses simple direct switching to control the compressor and that circuit is active whenever the ignition is on. So if you forget and leave the AC on the compressor will be engaged when cranking the engine.
