AC not working, clutch wont engage and is loud

[Duskope]

So im trying to fix my AC, the compressor wont kick on unless i jump the switch. Makes a somewhat grindy noise when it jumps on. When reading the low pressure gauge with the compressor on, it reads 0, and wont seem to fill up with refrigerant. Leak? Do I need a new compressor?

99 tahoe 2dr

Edit: Definitely a leak, got it to hold some and watched the pressure slowly drop

 

[JOHNGAAA1]

Compressor shot.

 

[8thNote]

So im trying to fix my AC, the compressor wont kick on unless i jump the switch. Makes a somewhat grindy noise when it jumps on. When reading the low pressure gauge with the compressor on, it reads 0, and wont seem to fill up with refrigerant. Leak? Do I need a new compressor?

99 tahoe 2dr

Edit: Definitely a leak, got it to hold some and watched the pressure slowly drop

It sounds like the compressor is good if it comes on when you jump it. It's likely noisy because there is no lubrication oil left in the system.

First step is to find the leak with a UV dye kit. Then repair the leak(s), add correct amount of refrigerant, and the correct amount (and type) of compressor oil.

In my experience, the AC systems in these GMT400 trucks are easy to repair and the compressors and other major components rarely go bad. Common areas for leaks are the low and high pressure switches, Schrader valve on low side port, poppet valve on high side port, and o-rings at connections. All inexpensive repairs. The high side poppet valve port should be replaced with an aftermarket Schrader valve port.

 

[Scooterwrench]

Compressor is post toasty,literally blown up internally. Good chance it has pushed chunks into the condenser. Pull the orifice tube,pretty sure it will be clogged with compressor guts. You may have to replace the condenser,it will be full of chunks too.

 

[GoToGuy]

You can use compressed air to find leaks. Although nitrogen is recommended. Compressed air then soapy water at all connections, fittings , hardware, compressor shaft, seals , junction block. Grinding, clunking, knocking noise from compressor= probably toast. Fix leaks, flush, R&R broken stuff. Vacuum down. Continue