A/C Compressor

When the A/C compressor is engaged, either from the bus from ACC or with the A/C button on the dashboard, DICE will check the refrigerant pressure, evaporator temperature and coolant temperature. If all the values are acceptable, A/C ON (Bus from DICE) will be sent. MIU will then apply battery voltage to the Trionic control module pin 59.

The control module opens the idle speed control valve slightly further to prepare for the impending increase in load. After a short delay, the control module will ground pin 54, which is connected tot he A/C relay.

The control module activates the relay only after the engine has started.

Diagnosis
- There is no diagnosis for the electric circuit to the relay.