My '12 fusion ac clutch doesn't engage unless the relay is bypassed.

I previously replaced the hvac control module. I just replaced the evap temp sensor and relay. Any ideas?

 

Part of the compressor control system uses high and low refrigerant pressure switches which are to protect the compressor if the pressure gets too high or the amount of refrigerant in the system is too low. The best thing to do is check the amount of refrigerant in the system with a set of A/C gauges. If the pressures are good then an electrical problem may exist.