Radiator Fan High Speed Circuit Troubleshooting

Radiator Fan High Speed Circuit Troubleshooting

1. Check the No. 6 (30 A) and the No. 15 (7.5 A) fuse in the under-hood fuse/relay box.

Are the fuses 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 PCM, the under-hood fuse/relay box and the radiator fan motor, the under-hood fuse/relay box and the A/C condenser fan motor, and the under-dash fuse/relay box connector terminal and the under-hood fuse/relay box

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





Is there battery voltage?

YES -

Go to step 4.

NO -

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

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





Does the radiator fan run at high speed?

YES -

Go to step 8.

NO -

Go to step 5.

5. Disconnect the radiator fan motor 2P connector, then test the fan motor Testing and Inspection.

Is the fan motor OK?

YES -

Go to step 6.

NO -

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

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





Is there continuity?

YES -

Go to step 7.

NO -

Repair an open in the wire between radiator fan motor 2P connector terminal No. 1 and body ground (G201).

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





Is there continuity?

YES -

Check for poor connections or loose terminals at the under-hood fuse/relay box and the radiator fan motor. If it is OK, replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.

NO -

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

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

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





Is there battery voltage?

YES -

Go to step 10.

NO -

Check the A/C diode B in the under-hood fuse/relay box. If the diode is OK, replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.

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 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 PCM from damage.

15. Disconnect PCM connector A (44P).

16. Check for continuity between PCM connector terminal A5 and radiator fan relay 4P socket terminal No. 3.





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 radiator fan relay 4P socket terminal No. 3 and PCM connector terminal A5.