Diesel Data: Automotive Repair

Radiator Fan Switch Circuit Troubleshooting (Open)

Radiator Fan Switch Circuit Troubleshooting (Open)

'00 - 05 models

1. Disconnect the radiator fan switch 2P connector.
2. Turn the ignition switch to ON (II).
3. Measure the voltage between the radiator fan switch 2P connector terminal No. 2 and body ground.





Is there battery voltage?

YES - Go to step 4.

NO - Repair open in the wire between the radiator fan switch 2P connector terminal No. 2 and main under-hood fuse/relay box.

4. Turn the ignition switch to LOCK (0), and check for continuity between the radiator fan switch 2P connector terminal No. 1 and body ground.





Is there continuity?

YES - Replace the radiator fan switch.

NO - Repair open in the wire between the radiator fan switch 2P connector terminal No. 1 and body ground. If the wire is OK, check for a poor ground at G301.