Have a 1992 740 turbo wagon. New a/c compressor. Was working fine, then the clutch electrics disappeared. If I run a wire from battery directly to the clutch input, all is OK. Think the CCU is defective. Anyone know how to remove this unit without damage to the dash? I have removed the plastic trim from around the CCU & have removed the 4 Phillips screws that secure the unit, but the unit will NOT pull out. Any help much appreciated. Thank you all.

 

first, check the pressure switch on the side of the 'beer can' reciever/dryer.... the signal from the CCU goes to this switch, then from the switch it goes to the compressor, so if the switch doesn't close, the compressor won't run. the switch is supposed to close if there's sufficient pressure (or maybe its if there's not too much pressure, I forget). anyways, you can unplug taht switch, and jumper the two pins of the harness plug together, and see if it works... if it does, then your CCU is fine, the problem is in the pressure or in the switch.