High Temperature Disable

A feed on a brown wire from fuse 7 (C573-4) in the engine compartment fusebox, passes to the relay module (C172-7). The feed passes through the cooling fan 2 relay whose contacts have been closed by the A/C grant. From the relay module (C172-5), the feed passes on a brown and red wire to the cooling fan motor (C005-1). The earth for the cooling fan motor (C005-2) passes to the relay module (C172-6) on a purple and slate wire. The earth path passes through the cooling fan 1 relay whose contacts have also been closed by the A/C grant. From the relay module (C172-4) the cooling fan motor is earthed on a black wire.

High Temperature Disable

The ECM can disable the A/C compressor clutch operation to reduce engine load when high engine temperatures are experienced.

If the ECM senses a coolant temperature of above 117.5 °C from the engine coolant temperature (ECT) sensor, the A/C grant is overridden by removing the earth path from the A/C condenser fan relay in the relay module at ECM connector (C126-9). The A/C compressor clutch relay is de-energized, disengaging the A/C compressor clutch. This condition will remain until the engine coolant temperature drops to 115 °C when the A/C grant will be reinstated.

Air Conditioning Condenser Fan - High Engine Temperature Grant

The ECM can override the condenser fan request and operate the fan during high engine temperatures to assist cooling. This can occur even if the A/C system is not operating. Both fans can run in two modes of operation; slow mode when each fan is connected in series with a common feed and fast mode when each fan is connected in parallel with separate feeds. Refer to Cooling Fan Operation - L Series for slow and fast mode cooling fan operation.