AC recharge question

I checked all over google and can't find the right answer. Plus it's fuckin hot out and I need to fix this. When I'm checkin the pressure at the low port, should the car be on or off with the AC blowing? Or should I not have the AC blowing at all? The readings are completely different depending on whether or not I have it running, and I can't find the manual for the product I'm using to tell me specifically. And it's been a long time since I've had to recharge an AC system but for some reason I'm thinking the car should be running with the AC going full blast. Am I wrong? I just want to make sure so I don't overfill it. Thanks

forget it, im retarded

ooooooooooooook

great. and i read that.

Where'd you get the freon and I promise I won't tell the FBI

Newer cars don't use freon.

Quote:

Originally posted by rainbowdemon

Newer cars don't use freon.

I know.