Was the air conditioning system working prior to the replacement of the compressor, condenser, expansion valve and pressure switch? Presume it was properly evacuated and recharged with the correct amount of refrigerant. After checking all fuses and relays, will start at the end of the system and work backwards to the beginning looking for any discrepancies i.e. continuity, voltage, etc. problems.
#NEVER GIVE UP
#AUDACITY OF HOPE
"Rather not run the risk of offending anyone, so let me just go ahead and offend someone". -PONY MAN
"When you write the story of your life, don't let anyone else hold the pen". -UNKNOWN