Condenser Fan: Description and Operation

System Outline

With the ignition SW turned on, the current through the ECU IG fuse flows to the FAN NO.1 relay (Coil side), FAN NO.2 relay (Coil side) and FAN NO.3 relay (Coil side).

1. Low Speed Operation
Only when the A/C system is activated, 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 FAN NO.3 relay (Coil side) to TERMINAL 2 of the diode (A/C) to TERMINAL 3 to TERMINAL (A) 16 of the engine control module, causing the FAN NO.3 relay to turn on. As a result, the current through the CDS FAN fuse flows to FAN NO.3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to TERMINAL 3 of the FAN NO.2 relay to TERMINAL 4 to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND. As this flowing in series for the motors, the motors rotate at low speed.

2. High Speed Operation
With the pressure SW is turned on and/or the water temp. SW is turned on, the A/C condenser fan motor and the radiator fan motor rotate at high speed.

When the pressure SW is turned on, the current through the ECU IG fuse flows to the FAN NO.1 and NO.2 relay (Coil side) to TERMINAL 3 of the pressure SW to TERMINAL 2 to GROUND, and the current through the ECU IG fuse flows to the FAN NO.3 relay (Coil side) to TERMINAL 2 of the diode (A/C) to TERMINAL 1 to TERMINAL 3 of the pressure SW to TERMINAL 2 to GROUND. As a result, FAN NO.1, NO.2. and NO.3 relay is turned on. At the same time, the current from the RDI FAN fuse flows to FAN NO.1 relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, and the current from the CDS FAN fuse flows to FAN NO.3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to TERMINAL 3 of the FAN NO.2 relay to TERMINAL 5 to GROUND.

As the current flowing in parallel for motors as above, the motors rotate at high speed.

When the water temp. SW is turned on, the current through the ECU IG fuse flows to the FAN NO.1 and NO.2 relay (Coil side) to TERMINAL 2 of the water temp. SW to TERMINAL 1 to GROUND, and the current through the ECU IG fuse flows to the FAN NO.3 relay (Coil side) to TERMINAL 2 of the diode (A/C) to TERMINAL 1 to TERMINAL 2 of the water temp. SW to TERMINAL 1 to GROUND. As a result, FAN NO.1, NO.2 and NO.3 relay is turned on. At the same time, the current from the RDI FAN fuse flows to FAN NO.1 relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, and the current from the CDS FAN fuse flows to FAN NO.3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to TERMINAL 3 of the FAN NO.2 relay to TERMINAL 5 to GROUND.

As the current flowing in parallel for motors as above, the motors rotate at high speed.