GMC Sierra 1500 Classic air conditioning

frustratedk

worked fine last year really hot this year. did work ok one day last week but now hot air. help please.

Mr_Shiftright

First thing you should do is check to see if your AC compressor clutch is engaging when you hit the AC switch. If it is not, you won't get any cold air of course. This could be a bad compressor clutch, or you could be low on, or empty of, refrigerant. The only way to test for proper refrigerant levels is to hook up to a machine for this purpose. If the refrigerant is too low, it will prevent the AC clutch from engaging, so just because the clutch doesn't engage, that doesn't necessarily mean it's bad.

Here's a short video that explains the procedure.

https://www.youtube.com/watch?v=E_9mGf8MP1c

There are also other possible causes, but these are the two most common.