Radiator Cooling Fan Motor: Testing and Inspection

NOTE: Overheating and Cooling system related problems can be the result either mechanical, electrical, or, since the engine cooling fan system is controlled by the Electronic Control Module (ECM), computer related failures. In order to properly diagnose the problem all related systems should be checked prior to reaching a conclusion.

1. Perform a visual inspection of the cooling system. Testing and Inspection
2. Since the engine cooling fan system is controlled by the Electronic Control Module (ECM), check the computer system for related trouble codes. If codes exist, service these first before proceeding.

BASIC TROUBLESHOOTING HINTS:
Electric Cooling fan does not work.

Possible Causes
1. No power to the electric cooling fan motor.
a. Inspect wiring to the electric cooling fan motor.
b. Visually inspect fusible links.
2. Inoperative electric cooling fan motor ground.
a. Check continuity of circuit from the electric cooling fan motor to ground.
3. Inoperative electric cooling fan motor.
a. If all wires are OK, disconnect the cooling fan motor electrical connection, and with a fused jumper wire, apply battery voltage and ground to the cooling fan.
b. If the electric cooling fan does not run at high speed, the electric cooling fan motor is defective and should be replaced.
c. If the electric cooling fan runs at high speed, the cooling fan motor is OK. The electric cooling fan computer related systems need to be inspected. Since the engine cooling fan system is controlled by the Electronic Control Module (ECM), for testing the electric cooling fan motor systems that are part of the computer controlled system, go to Powertrain Management/Computers and Control Systems/Testing and Inspection/Procedures/Diagnostic Charts (Pinpoint Tests)/Integrated Relay Control Module.