Ive always heard that you should turn the AC off when you shut the truck off... but no one can ever explain why. So thats my question, do I have to turn the AC off before I shut the truck off? will the ac last longer if I do this? If so, WHY?
I know one of you experts out there knows....

thanks

 

Mine is always on. I have remote start, I leave the air on so it starts when I start the truck.

 

I dont do mine although I do try to remember to turn everything off as a safe habit. In older cars it added more strain to trying to start an engine.

 

I turn the ac off, but leave the fan on, a half a block before my destination to prevent mildew from growing in the condensation.

 

thats ususally what I do too... not to prevent condensation, but just because...
so leaving it on doesnt put any strain on anything else? is it under pressure when you leave it on and shut the truck off?

 

+1 In the past, the starter was having to spin the compressor, too. These days the compressor doesn't kick on 'til the motor is running.

 

+2 More of an older car thing.

 

I do this in all of my cars as well. Helps dry out the evaporator.

 

yeh this isnt an issue anymore with computer controlled everything

 

Don't worrie about it. It really doesnt matter at all. There is a relay that shuts off the compressor for a few seconds then allows the compressor clutch to ingage once the motor is running.