volvo Workshop Repair Guides

Volvo Workshop Service and Repair Manuals

Control Module HVAC > < Blower Motor Relay|Service and Repair
Page 1
background image

Compressor Clutch Relay: Description and Operation

Compressor Cut-out

Purpose:

Allows ECU to control AC compressor clutch operation.

Operation:

If AC switch is operated with blower motor "ON," the ECU activates the AC relay.  Compressor cycling is controlled by the low pressure switch.

AC compressor is switched out under the following conditions:
- Full acceleration.  Under full throttle acceleration, compressor clutch is cut out for 15 seconds maximum (5 seconds minimum).
- Excessive coolant temperature.  If coolant temperature exceeds 255° F, compressor is cut out to prevent further overheating.

Control Module HVAC > < Blower Motor Relay|Service and Repair