A/C problem

When you say pressure relief valve, are you meaning the pressure sensor?

We need to check where we have voltage on the relay. We should have voltage at the top two terminals so we need to start with that. Then if you jump power to the lower right terminal of the relay the compressor should come on. I assume you were jumping power directly to the compressor, in which case we need to jump the relay to find out if the wiring to the compressor is okay.

As we work through this we will need to eliminate the different components. We have two sides to this system. The actual compressor side and then the control side. Both sides can cause the compressor to not come on. It sounds like you have proven the compressor is okay, now we just need to confirm the wiring is okay and go from there. Thanks