AC compressor issue

I would not say that I have a complete idea on what is going on, but it sounds like the A/C clutch is going bad. If I remember correctly it works pretty much like a manual transmission clutch it grabs on and begins making friction to make the A/C move and pump the fluid. I would wait until an actual expert gives an answer, but I would say your best bet is to buy a new A/C compressor.

Hi and thanks for using 2CarPros.com.

I am a bit confused on why the brakes would turn off the AC. However, lets start by checking the AC clutch to make sure it is not going bad. Here are specific directions from Alldata indicating how to check. The picture I attached correlates with these directions.

INSPECTION
CHECK THE MAGNETIC CLUTCH FOR A/C COMPRESSOR
Connect the connector battery to positive battery terminal in the A/C compressor, and then ground the battery (-) terminal to the A/C compressor itself. At this time, check that the magnetic clutch operating sound can be heard.

Let me know what you find or if the problem is different that I understood. I did double check wiring schematics, and the brake lights / switch are in no way tied into the power supply to the compressor. If you find the compressor clutch works correctly with the test, it's time to start looking for a loose or damaged connection or a wiring issue.

Here are some a few links which describe how to use a test light, volt meter, and how to check wiring.

I thought these links may be helpful if you are just starting out.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-check-wiring

I hope this information is helpful. As far as the compressor, it is most likely fine. The clutch can go bad, but based in your description, I feel there is a wiring issue (bad connection, corrosion, damaged connector or wiring.)

Take care and let me know if you have other questions or need additional help.

JOe