Radiator Fan Circuit Troubleshooting

Radiator Fan Circuit Troubleshooting

1. Check the No. 4 (20 A) fuse in the under-hood fuse/relay box and No. 14 (10 A) fuse in the driver's under-dash fuse/relay box.

Are the fuse(s) OK?

YES -

Go to step 2.

NO -

Replace the fuse(s) and recheck. If the fuse continues to blow, locate and repair the short in the circuit between the under-hood fuse/relay box and the radiator fan motor and driver's under-dash fuse/relay box connector terminal J1 and under-hood fuse/relay box connector terminal D8.

2. Remove the radiator fan relay from the under-hood fuse/relay box, and test it Testing and Inspection.

Is the relay OK?

YES -

Go to step 3.

NO -

Replace the radiator fan relay.�

3. Measure the voltage between radiator fan relay 4P socket terminal No. 2 and body ground.





Is there battery voltage?

YES -

Go to step 4.

NO -

Replace the under-hood fuse/relay box.�

4. Connect radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.





Does the radiator fan run?

YES -

Go to step 9.

NO -

Go to step 5.

5. Test the radiator fan motor Testing and Inspection.

Is the motor OK?

YES -

Go to step 6.

NO -

Replace the radiator fan motor Service and Repair.

6. Disconnect the radiator fan motor 2P connector.

7. Check for continuity between radiator fan relay 4P socket terminal No. 1 and radiator fan motor 2P connector terminal No. 2.





Is there continuity?

YES -

Go to step 8.

NO -

Repair an open in the wire between the under-hood fuse/relay box and radiator fan motor 2P connector terminal No. 2.�

8. Check for continuity between radiator fan motor 2P connector terminal No. 1 and body ground.





Is there continuity?

YES -

Check for poor connections or loose terminals at the under-hood fuse/relay box, the radiator fan motor and body ground G201.�

NO -

Repair an open in the wire between radiator fan motor 2P connector terminal No. 1 and body ground G201. If the wire is OK, check for a poor ground at G201.�

9. Disconnect the jumper wire, and turn the ignition switch to ON (II). Measure the voltage between radiator fan relay 4P socket terminal No. 3 and body ground.





Is there battery voltage?

YES -

Go to step 10.

NO -

Repair an open in the wire between under-hood fuse/relay box connector terminal J1 and driver's under-dash fuse/relay box connector terminal D8.�

10. Turn the ignition switch to LOCK (0).

11. Connect the HDS to the DLC.

12. Turn the ignition switch to ON (II).

13. Make sure the HDS communicates with the vehicle and the ECM/PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.

14. Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).

NOTE: This step must be done to protect the ECM/PCM from damage.

15. Disconnect ECM/PCM connector E (31P), then check for continuity between radiator fan relay 4P socket terminal No. 4 and ECM/PCM connector terminal E12.





Is there continuity?

YES -

Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known good ECM/PCM, replace the original ECM/PCM ECM/PCM Replacement (A/T).�

NO -

Repair an open in the wire between radiator fan relay 4P socket terminal No.4 and ECM/PCM connector terminal E12.�