Radiator Cooling Fan: Description and Operation

SYSTEM OUTLINE

FAN MOTOR OPERATION When the ignition SW is turned on, the current from the IGN fuse flows to the FAN NO.1 relay (Coil side) and the FAN NO.2 relay (Coil side) to TERMINAL 3 of the A/C single pressure SW to TERMINAL 2 to TERMINAL 2 of the water temp. SW to TERMINAL 1 to GROUND, and the FAN NO.1 relay is turned off and the FAN NO.2 relay is turned on.

- Low speed operation
When the ignition SW is turned on and the A/C is activated, current flows from the A/C COMP relay (Point side) to the FAN NO.3 relay (Coil side) to GROUND, and the FAN NO.3 relay is turned on. As a result, current from the CDS FAN fuse flows to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to the FAN NO.2 relay (Point side) to the FAN NO.3 relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, rotating both of the fan motors at low speed. If the engine coolant temperature is approx. 90°C (194°F) or less, and the refrigerant pressure is approx. 15.5 kgf/sq.cm (1520 kpa, 220.4 psi) or less, both the water temp. SW and the A/C signal pressure SW are closed, so that the FAN NO.1 relay is turned off and the FAN NO.2 relay is turned on. As a result, both of the fan motor operate at low speed.

- High speed operation
When, during A/C operation, the refrigerant pressure becomes higher than ordinary level (Approx. 15.5 kgf/sq.cm (1520 psi, 220.4 kpa)), the A/C single pressure SW is turned off. As a result, the FAN NO.1 relay is turned on and FAN NO.2 relay is turned off, and the current flows from the RDI FAN fuse to FAN NO.1 relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, and current from the CDS FAN fuse flows to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to the FAN NO.2 relay (Point side) to GROUND, rotating both of the fan motors in parallel, thus causing the fan motors to operate at high speed. Note that, because the current flows in the same manner even if the coolant temperature is approx. 90°C (194°F) or higher, the fan motors still operate at high speed.