A/C and fan clutch problem?? 05 KW t800b w/isx-500
 

Here goes. Our shop has a KW T800B w/ a cummins ISX-500 13spd. Every time at the same time the Air conditioning quits working as in the compressor quits running along with the engine fan locks up and runs non stop. Engine fan is air controlled. The local KW shop in Buda has replaced:

Fan Clutch, fan solenoid, pins to ecm connector for solenoid, fan switch in cab, expansion valve, a/c high pressure switch, dryer, egr multiple times, reflashed ecm, etc.

The problem still remains. I don't know which one is causing which one to fail. The a/c when it was working has correct charge, correct pressures. Both us and KW checked this. Any suggestions??

Thanks.