Cooling Fan Inoperative

Cooling Fan Inoperative

Circuit/System Description

The engine cooling fan system consists of one cooling fan and one relay. The relay is powered by the battery positive voltage circuit and controlled by a switched ground from the engine control module (ECM).

During operation, the ECM supplies the ground path for the cooling fan relay, which is relay 1, through the cooling fan relay control circuit. This energizes the cooling fan relay coil, closes the relay contacts, and supplies battery positive voltage from the cooling fan fuse through the cooling fan motor supply voltage circuit to the cooling fan. The cooling fan motor is grounded through its own ground circuit.


Circuit/System Verification

1. If DTC P0480 is set, then perform that diagnostic first.
2. Ignition ON, command the relay ON and OFF with a scan tool. Observe to verify that the fan turns ON and OFF with each command.

Circuit/System Testing

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the relay.
2. Connect a 30A fused jumper between the positive terminal at the battery and the fan voltage supply circuit terminal at the relay connection and verify fan activation.
* If the fan does not activate, test the fan voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the fan ground circuit for an open/high resistance. If the fan did not activate and the circuits test normal, replace the fan.

3. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the relay connection and verify fan activation.
* If the fan does not activate, test the relay switch voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.

4. If the fan and all circuits test normal, replace the relay.

Repair Instructions

* Cooling Fan and Shroud Replacement
* Fan Shroud Replacement
* Engine Control Module Replacement for the 2.2L engine
* Engine Control Module Replacement for the 2.4L engine

Repair Verification

Ignition ON, command the relay ON and OFF with a scan tool. Observe to verify that the fan turns ON and OFF with each command.