Radiator Fan High Speed Circuit Troubleshooting
Radiator Fan High Speed Circuit Troubleshooting
1. Check the No. 3-6 (30 A) fuse in the under-hood fuse/relay box and No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box.
Are the fuses OK?
YES -
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. 3-6 (30A) fuse and the No. 16 (7.5A) fuse circuit.�
2. Disconnect and remove the radiator fan relay and the relay circuit board 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 radiator fan relay and the relay circuit board OK?
YES -
Go to step 3.
NO -
Replace the radiator fan relay and/or the relay circuit board.�
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.�
5. Turn the ignition switch to ON (II).
6. Measure the voltage between under-hood fuse/relay box connector terminal B2 and body ground.
Is there battery voltage?
YES -
Turn the ignition switch to LOCK (0), then go to step 7.
NO -
Repair an open in the wire between driver's under-dash fuse/relay box connector terminal F26 and under-hood fuse/relay box connector terminal B2.�
7. Check for continuity between radiator fan relay 4P socket terminal No. 4 and under-hood fuse/relay box connector terminal B10.
Is there continuity?
YES -
Go to step 8.
NO -
Replace the under-hood fuse/relay box.�
8. Disconnect the radiator fan motor 2P connector.
9. 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 -
Go to step 10.
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.�
10. Check for continuity between radiator fan motor 2P connector terminal No. 1 and under-hood fuse/relay box connector B11.
Is there continuity?
YES -
Go to step 11.
NO -
Repair an open in the wire between radiator fan motor 2P connector terminal No. 1 and under-hood fuse/relay box connector B11.�
11. Check for continuity between under-hood fuse/relay box connector B1 and body ground.
Is there continuity?
YES -
Go to step 12.
NO -
Repair an open in the wire between under-hood fuse/relay box connector B1 and body ground. If the wire is OK, check for a poor ground at G301.�
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 ECM/PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.
15. 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.
16. Disconnect ECM/PCM connector A (49P)
17. Check for continuity between radiator fan relay 4P socket terminal No. 3 and ECM/PCM connector terminal A5.
Is there continuity?
YES -
Go to step 18.
NO -
Repair an open in the wire between under-hood fuse/relay box 4P socket terminal No. 3 and ECM/PCM connector terminal A5.�
18. Check for continuity between under-hood fuse/relay box connector D10 and ECM/PCM connector terminal A6.
Is there continuity?
YES -
Update the ECM/PCM if it does not have the latest software ECM/PCM Update (M/T), 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 Service and Repair.�
NO -
Repair an open in the wire between under-hood fuse/relay box connector D10 and ECM/PCM connector terminal A6.�