Lately my ac has been less that cold, then times it was more than cold. I know that this can be as simple as adding some Freon, but i have no cold air went out. My question is before purchase Freon is there a way to see if its just that? When i cut on the ac through the relay there is no grinding or mechanical noises. My rpms are not lowering like they used to when i turned on the ac, so i am thinking this might be meaning the compressor is bad, i want to know exactly where its located in the serpentine belt line to see if when the relay comes on if the clutch is engaging. Does anyone know how to test this? How can i see if its just the Freon?