Radiator Cooling Fan Always On

*RADIATOR COOLING FAN ALWAYS ON









For a complete Radiator Cooling Fan Circuit Diagram, Refer to COOLING - SCHEMATICS AND DIAGRAMS. [1][2]Electrical Diagrams

Diagnostic Test

1. CHECKING DRB III(R) FOR A/C SWITCH STATUS





Turn the ignition on.

Insure that the A/C Switch is off.

With the DRB III(R) in Inputs/Outputs, check the status of the A/C Switch.

Does the DRB III(R) display Air Conditioning ON?

Yes

- Repair the A/C Switch circuit.
- Perform POWERTRAIN VERIFICATION TEST - VER 3. Powertrain Verification Test - Ver 3

No

- Go to 2

2. CHECKING THE RADIATOR FAN CONTROL MODULE OUTPUT CIRCUIT





Turn the ignition off.

Disconnect the Radiator Fan Control Module harness connector.

Disconnect the Radiator Fan Motor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.

Measure the voltage on the Radiator Fan Control Module Output circuit.

Is the voltage below 1.0 volt?

Yes

- Go to 3

No

- Repair the Radiator Fan Control Module Output circuit for a short to voltage.
- Perform POWERTRAIN VERIFICATION TEST - VER 3. Powertrain Verification Test - Ver 3

3. CHECKING THE RADIATOR FAN CONTROL CIRCUIT





Turn the ignition off.

Disconnect the Powertrain Control Module (PCM) C4 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the Radiator Fan Control circuit.

Is the resistance above 100 kohms?

Yes

- Go to 4

No

- Repair the Radiator Fan Control circuit for a short to ground.
- Perform POWERTRAIN VERIFICATION TEST - VER 3. Powertrain Verification Test - Ver 3

4. CHECKING THE POWERTRAIN CONTROL MODULE





With the ignition off.

Reconnect the PCM C4 harness connector.

Measure the resistance between ground and the Radiator Fan Control circuit at the Radiator Fan Control Module harness connector.

Is the resistance above 100 kohms?

Yes

- Replace the Radiator Fan Control Module.
- Perform POWERTRAIN VERIFICATION TEST - VER 3. Powertrain Verification Test - Ver 3

No

- Replace the Powertrain Control Module.
- Perform POWERTRAIN VERIFICATION TEST - VER 3. Powertrain Verification Test - Ver 3