Radiator Cooling Fan Always on

*RADIATOR COOLING FAN ALWAYS ON





POSSIBLE CAUSES
- RADIATOR FAN CONTROL CIRCUIT SHORTED TO GROUND
- RADIATOR FAN CONTROL MODULE OUTPUT CIRCUIT SHORTED TO VOLTAGE
- RADIATOR FAN CONTROL MODULE
- A/C SWITCH CIRCUIT MALFUNCTION
- POWERTRAIN CONTROL MODULE
- For a complete Radiator Cooling Fan Circuit Diagram, (Refer to - COOLING - SCHEMATICS AND DIAGRAMS).

Diagnostic Test
1. CHECKING DRBIII � FOR A/C SWITCH STATUS





Turn the ignition on.
Insure that the A/C Switch is off.
With the DRBIII in Inputs/Outputs, check the status of the A/C Switch.
Does the DRBIII � 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.