Checking Radiator Fan Performance With No DTCS: 4.0L
- Turn ignition on. With the DRBIII®, actuate the Radiator Fan Relay. Does the Radiator Fan Motor cycle on and off? If yes, test is complete. If no, go to next step.
- With the DRBIII®, actuate the Radiator Fan Relay. Using a 12-volt test light connected to ground, backprobe the Radiator Fan Relay Output circuit in the Radiator Fan Motor harness connector. Does the test light cycle on and off? If yes, go to next step. If no, go to step 5.
- Turn ignition off. Disconnect the Radiator Fan Motor harness connector. Measure the resistance between ground and the Radiator Fan Motor Ground circuit at the Radiator Fan Motor harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the Radiator Fan Ground Circuit for an open.
- If there are no possible causes remaining, replace the Radiator Fan Motor.
- Turn ignition off. Disconnect the Radiator Fan Relay connector. Using a 12-volt test light connected to ground, check the Fused B(+) circuit in the Radiator Fan Relay connector. Did the test light illuminate brightly? If yes, go to next step. If no, repair the Fused B(+) circuit for an open. Also check fuse for Radiator Fan Relay in PDC.
- Disconnect the Radiator Fan Motor harness connector. Measure the resistance of the Radiator Fan Relay Output circuit between the Radiator Fan Motor harness connector and the Radiator Fan Relay harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the Radiator Fan Relay Output Circuit for an open.
- There are no possible causes remaining, replace the Radiator Fan Relay.