Radiator Fan Circuit Troubleshooting

Radiator Fan Circuit Troubleshooting





1. Check the No. 57 (20 A) fuse in the main underhood fuse/relay box, and the No. 20 (7.5 A) fuse in the under-dash fuse/relay box.
Is the fuse(s) OK?
YES - Go to step 2.
NO - Replace the fuse(s) and recheck.
2. Remove the radiator fan relay from the main underhood fuse/relay box, and test it.
Is the relay OK?
YES - Go to step 3.
NO - Replace the radiator fan relay.
3. Measure the voltage between the No. 1 terminal of the radiator fan relay 4P socket and body ground.
Is there battery voltage?
YES - Go to step 4.
NO - Replace the main under-hood fuse/relay box.





4. Connect the No. 1 and No. 2 terminals of the radiator fan relay 4P socket with a jumper wire.
Does the radiator fan run?
YES - Go to step 5.
NO - Go to step 6.





5. Disconnect the jumper, and turn the ignition switch ON (II). Check for voltage between the No. 3 terminal of the radiator fan relay 4P socket and body ground.
Is there battery voltage?
YES - Go to step 9.
NO - Check for an open in the BLK/YEL wire between the main under-hood fuse/relay box and the under-dash fuse/relay box.
6. Disconnect the radiator fan connector.





7. Check for continuity between the No. 2 terminal of the radiator fan relay 4P socket and the No. 2 terminal of the radiator fan connector.
Is there continuity?
YES - Go to step 8.
NO - Repair open in the BLU/BLK wire between the main under-hood fuse/relay box and the radiator fan.





8. Check for continuity between the No. 1 terminal of the radiator fan connector and body ground.
Is there continuity?
YES - Replace the radiator fan motor.
NO - Check for an open in the BLK wire between the radiator fan connector and body ground. If the wire is OK, check for a poor ground at G201.
9. Reinstall the radiator fan relay.
10. Disconnect the radiator fan switch connector. Jump terminals 1 and 2 to see if fan runs.
Does the fan run?
YES - Replace the radiator fan switch.
NO - Go to step 11.





11. Remove the jumper, and measure the voltage between the No. 2 terminal on the radiator fan switch connector and body ground.
Is there battery voltage?
YES - Check for an open in the BLK wire between the radiator fan switch connector and body ground. If the wire is OK, check for a poor ground at G301 .
NO - Repair open in the GRN wire between the radiator fan switch connector and the main underhood fuse/relay box..