Radiator Cooling Fan Motor: Description and Operation

DESCRIPTION
The electro-drive cooling fan system consists of a two-speed fan electric motor. The cooling fan is controlled during engine operation by the Electronic Control Module (ECM) and the Integrated Relay Control Assembly.

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

OPERATION
The electro-drive cooling fan is wired to operate only when the ignition switch is in the RUN position, thereby preventing cooling fan operation after the ignition switch is turned to the OFF position. The cooling fan is controlled during vehicle operation by the Integrated Relay Control Assembly and ECM, which will energize the cooling fan under the following conditions:
1. The cooling fan will run at low speed if:
a. If the engine temperature is higher than normal. (Fan 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. (Fan starts running at speeds at or below 69 km/h (43 mph) and stops running at 77 km/h (48 mph).

NOTE: Normal operation and cycling of the engine cooling fan will cause the temperature gauge indicator to read between the mid-point and upper portion of the temperature gauge scale. The slightly higher indicator reading will return to mid-point when fan operation begins.

2. The cooling fan will run on high speed if:
a. The engine temperature is higher than desirable and the fan has been operating at low speed. Fan starts running at high speed at 111° C (230° F) and stops running at 107°C (224° F).