Prelude L4-1955cc 2000 (1987)
Condenser Fan: Description and Operation
Radiator and A/C Condenser Fans
The radiator and A/C condenser fan motors operate with the ignition switch in "RUN" and the temperature of the coolant in the radiator above 199
degrees F (93 degrees C). If the car is equipped with air conditioning, the radiator fan motor and A/C condenser fan motor both operate with the
coolant above 199 degrees F (93 degrees C) or with the A/C compressor clutch engaged. With the coolant above 199 degrees F (93 degrees C),
current flows through the radiator fan relay coil and radiator fan temperature switch to ground. The relay contacts close, and current flows through the
radiator fan motor to ground. The motor operates.
With the fuel injected engine, the radiator fan control unit receives inputs from the radiator fan temperature switch and the under-hood temperature
switch. With the engine running and the coolant temperature above 199 degrees F, the control unit applies voltage to the coil of the radiator fan relay.
The relay contacts close and voltage is applied to the radiator fan motor. The motor operates without the engine running and the under-hood
temperature above 107 degrees F, the radiator fan control unit receives an input from the closed contacts of under-hood temperature switch. The
radiator fan motor operates the same way as with the engine running, but it only runs for a maximum of 15 minutes or until the under-hood
temperature switch opens.
With the carbureted engine and the A/C switch on the heater control panel closed, current flows through the radiator fan relay coil, the A/C diode box,
the A/C dual pressure cutout switch, the A/C thermostat, and the A/C switch to ground.The radiator fan relay contacts close and current flows through
the relay and both fan motors to ground.
With the fuel injected engine and the A/C switch closed, the radiator fan control unit receives an A/C on input. The control unit applies voltage to the
coil of the radiator fan relay and the sub radiator fan relay. The relays contacts close an both fan motors operate.