Compressor Clutch: Description and Operation

System Protection

Power to the compressor clutch may be cut should either the engine management or air conditioning control systems detect certain conditions; these conditions may be caused by Fault or Demand and can be classified thus:

Fault
- Engine coolant overheat.
- Refrigerant excessive pressure.
- Refrigerant, insufficient pressure or low charge weight.
- Speed differential between compressor and crankshaft caused by belt slippage or compressor seizure (indicated by A/C state lamp flashing once per second) 12 cylinder engine only. This feature, 'lock sensing' is fully explained in the EDM.

Demand
- Engine maximum power requirement
- Electrical system drain at engine idle.