AC stopped working?

If it is the compressor clutch that is not kicking in, then you have to perform test to find out what is wrong.

When the compressor cuts out, are the cooling fans staying on? If yes, then the problem is from the clutch.

If the cooling fans stops as well, then it could be a faulty magnetic clutch relay or its controlling circuit.

If you are able to perform diagnostics, get a DVOM and test lamp.

Was the freon topped up recently?
Are the cooling fans working when the compressor is engaged?
Do you have engine overheating issues?

Hi,

I guess I don't quite understand what the mechanic thinks it is then? If the wiring checks out and the relay is okay then the PCM is one of the only things left other than a possible sensor that is telling the PCM to not turn the compressor on.

Does the compressor clutch come on at all? You can try jumping power to the compressor and making sure the compressor comes on. Once that is okay then we can start looking at the PCM.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak