Yukon XL AC switch or compressor problems

I have a 2001 GMC Yukon Xl 1500 2WD with a 5.3 engine. It has about 165,000 miles on it and I have been experiencing AC problems for about 2 years now. I had 1 mechanic replace the compressor. That went out and it was replaced again. That also went out and I went to another mechanic. He flushed out the whole system and replaced the compressor, the rear evap valve, the dryer, the accumulator, the orifice tube and he said the evaporator was clogged. He finally cleared that out and then he told me that the system would not work because the compressor was shorting out. In fact, he replaced the new compressor with the older one and said that the older one was still working, but that there was a short outside of the compressor. He told me I needed to go to an auto electric shop to find out why the AC compressor works when manually bypassed but will not come on when the wires are connected (not sure which wires he’s talking about).

My question – does this sound like a common problem with one of the switches (A/C Clutch Cycling Switch, A/C Pressure Switch, High Pressure Cutout Switch, Low Pressure Cutout Switch, A/C Pressure Cut-Off Switch, A/C Switch Connector, the A/C Compressor Control Relay or the A/C Compressor Relay). I am not sure what these switches do, but that’s what I’ve come up with on my research. :banghead: