Radiator Fan High Speed Circuit Troubleshooting

Radiator Fan High Speed Circuit Troubleshooting

1. Check the No. A3-6 (30 A) fuse in the under-hood fuse/relay box and the No. B16 (7.5 A) fuse in the driver's under-dash fuse/relay box.

Are the fuse(s) OK?

YES -

Reinstall the fuse(s), then go to step 2.

NO -

Replace the fuse(s) and recheck. If the fuse(s) blow again, repair the short to ground on the No. A3-6 (30 A) fuse, and the No. B16 (7.5 A) fuse circuit.

2. Disconnect and remove the relay circuit board and the radiator fan relay from the under-hood fuse/relay box, then test the radiator fan relay Testing and Inspection and relay circuit board Testing and Inspection.

Are the relay circuit board and/or the radiator fan relay OK?

YES -

Go to step 3.

NO -

Replace the relay circuit board and/or the radiator fan relay.

3. Test the radiator fan motor Testing and Inspection.

Is the motor OK ?

YES -

Go to step 4.

NO -

Replace the radiator fan motor Radiator And A/C Condenser Fan, Motor, And Shroud Removal And Installation.

4. Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.





Is there battery voltage?

YES -

Go to step 5.

NO -

Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.

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

6. Measure the voltage between under-hood fuse/ relay box connector terminal B12 and body ground.





Is there battery voltage?

YES -

Go to step 7.

NO -

Repair an open in the wire between driver's under-dash fuse/relay box connector terminal F29 and under-hood fuse/relay box connector terminal B12.

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

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





Is there continuity?

YES -

Go to step 9.

NO -

Repair an open in the wire between fan relay 4P socket connector terminal No. 2 and radiator fan motor 2P connector terminal No. 1.

9. Check for continuity between under-hood fuse/ relay box connector terminal B10 and radiator fan motor 2P connector terminal No. 2.





Is there continuity?

YES -

Go to step 10.

NO -

Repair an open in the wire between the under-hood fuse/relay box connector terminal B10 and radiator fan motor 2P connector terminal No. 2.

10. Check for continuity between under-hood fuse/ relay box connector terminal B6 and body ground.





Is there continuity?

YES -

Go to step 11.

NO -

Repair an open in the wire between under-hood fuse/relay box connector terminal B6 and body ground. If the wire is OK, check for a poor ground G301.

11. Check for continuity between radiator fan relay 4P socket terminal No. 3 and under-hood fuse/relay box connector terminal B11.





Is there continuity?

YES -

Go to step 12.

NO -

Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.

12. Connect the HDS to the DLC.

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

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

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

16. Jump the SCS line with the HDS.

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

17. Disconnect PCM connector A (49P).

18. Check for continuity between radiator fan relay 4P socket terminal No. 4 and PCM connector terminal A44.





Is there continuity?

YES -

Go to step 19.

NO -

Repair an open in the wire between radiator fan relay 4P socket terminal No. 4 and PCM connector terminal A44.

19. Check for continuity between under-hood fuse/relay box connector terminal D5 and PCM connector terminal A45.





Is there continuity?

YES -

Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM, then recheck . If the symptom/indication goes away with a known good PCM, replace the original PCM Service and Repair.

NO -

Repair an open in the wire between under-hood fuse/relay box connector terminal D5 and PCM connector terminal A45.