Fan Motor Relay and A/C Medium Pressure Switch

OPERATION
The engine control module controls the power transistors (at the low and high speed sides) to operate the radiator fan motor and condenser fan motor at speeds suitable for the engine coolant temperature and vehicle speed.

When the engine control module causes the power transistor in the module to be ON, current flows through the fan motor relay coil to the engine control module.

When the fan motor relay coil is energized, the switch of the relay is caused to be ON to supply the motor drive power to the radiator fan motor and condenser fan motor through the respective relay switches from the battery. When the air conditioning switch and air conditioning refrigerant medium pressure switch are ON, the radiator fan motor and condenser fan motor rotate at high speed regardless of the vehicle speed and engine coolant temperature.