Radiator Cooling Fan Motor: Description and Operation

With the ignition SW turned ON, the current through ECU-IG fuse flows to the Radiator Fan Relay (coil side), Radiator Fan Relay No.2 (coil side) and the Radiator Fan Relay No.3 (coil side).Furthermore, the current through the Radiator Fan Relay (coil side) or the Radiator Fan Relay No.2 (coil side) flows to the A/C single pressure SW --> the engine coolant temp. SW --> GROUND, causing the Radiator Fan Relay No.2 to turn ON.

1. LOW SPEED OPERATION
Only when the A/C system is activated or the engine coolant temp. SW No.2 is turned ON, the A/C Condenser Fan Motor and the Radiator Fan Motor rotates at low speed.
When the A/C system is activated, the current from ECU-IG fuse flows to the Radiator Fan Relay No.3 (coil side) --> Diode --> TERMINAL 12 of the A/C amplifier, causing the Radiator Fan Relay No.3 to turn ON. As a result, the current through CDS fuse flows to TERMINAL 2 of the A/C Condenser Fan Motor --> TERMINAL 1 --> TERMINAL 3 of the Radiator Fan Relay No.2 --> TERMINAL 5 --> TERMINAL 5 of the Radiator Fan Relay No.3 --> TERMINAL 3 --> TERMINAL 2 of the Radiator Fan Motor --> TERMINAL 1 --> GROUND. As this flowing in series for the Motors, the Motors rotate at low speed.
When the engine coolant temp.SW is turned ON, the current from ECU-IG fuse flows to the Radiator Fan Relay No.3 (coil side) --> TERMINAL 1 of the engine coolant temp. SW No.2 --> GROUND, causing the Radiator Fan Relay No.3 to turn ON. As a result, the current through CDS fuse flows same route as above, rotating the Motors at low speed.

2. HIGH SPEED OPERATION
Only when the A/C single pressure SW is turned OFF or the engine coolant temp. SW is turned OFF, the A/C Condenser Fan Motor and Radiator Fan Motor rotates at high speed.
When the A/C single pressure SW is turned OFF, the current from RDI FAN fuse flows to the Radiator Fan Relay (point side) --> the Radiator Fan Motor --> GROUND. At the same time, the current from CDS FAN fuse flows to the A/C Condenser Fan Motor --> TERMINAL 3 of the Radiator Fan Relay No.2 --> TERMINAL 4 --> GROUND.
As the current flowing in parallel for the Motors as above, the Motors rotate at high speed.