Radiator Fan Switch Circuit Troubleshooting

Radiator Fan Switch Circuit Troubleshooting (Open)
1. Disconnect the radiator fan switch 2P connector.
2. Turn the ignition switch ON (II).





3. Measure voltage between the No. 2 terminal of the radiator fan switch 2P connector 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 underhood fuse/relay box.





4. Turn the ignition switch OFF, and check for continuity between the No. 1 terminal of the radiator fan switch 2P connector and body ground.
Is there continuity?
YES - Replace the radiator fan switch.
NO - Check for an 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.

Radiator Fan Switch Circuit Troubleshooting (Short)
1. Remove the radiator fan relay from the main underhood fuse/relay box, and test it.
Is the relay OK?
YES - Go to step 2.
NO - Replace the radiator fan relay.
2. Remove the radiator fan switch, and test it.
Is the radiator fan switch OK?
YES - Go to step 3.
NO - Replace the radiator fan switch.
3. Disconnect the negative cable from the battery.
4. Disconnect Engine Control Module (ECM) connector A (25P) and the under-hood fuse/relay box 16P connector.





5. Check for continuity between the No. 2 terminal of the radiator fan switch 2P connector and body ground.
Is there continuity?
YES - Repair short in the wire between the radiator fan switch 2P connector terminal No. 2 and main under-hood fuse/relay box.
NO - Replace the main under-hood fuse/relay box.