Radiator Cooling Fan Motor: Description and Operation

DESCRIPTION
The fan control system consists of:
1. A two-speed cooling fan motor.
2. The cooling fan motor is wired to operate only when the ignition switch is in the RUN position, thereby preventing cooling fan motor operation after the ignition switch is turned to the OFF position.

WARNING: Disconnect the cooling fan motor prior to performing any underhood service since the cooling fan motor could cycle if the ignition switch is left in the ON position even though the engine is not running.

OPERATION
The cooling fan system is controlled during vehicle operation by the Constant Control Relay Module (CCRM) and the Powertrain Control Module (PCM) which will energize the cooling fan motor under the following conditions:
1. The cooling fan motor is turned on low speed if:
a. Engine temperature is higher than normal. Radiator electric motor starts running at 102° C (215° F) and stops running at 99° C (210° F).
b. A/C is on and vehicle speed does not provide enough natural airflow. Cooling fan motor starts running at speeds at or below 69 km/h (43 mph) and stops running at 77 km/h (48 mph).
2. Cooling fan will run at high speed if:
a. Engine temperature is higher than desirable and cooling fan motor has been operating at low speed. Cooling fan motor starts running at high speed at 110° C (230° F) and stops running at 107° C (224° F).

NOTE: The normal operation and cycling of the cooling fan motor causes the temperature gauge indicator to read between the mid-point and upper portion of the temperature gauge scale. The slightly higher indicator reading returns to mid-point when cooling fan motor operation begins.