Radiator Fan High Speed Circuit Troubleshooting
Radiator Fan High Speed Circuit Troubleshooting
NOTE: Before performing symptom troubleshooting, check for powertrain DTCs Initial Inspection and Diagnostic Overview.
1. Check the No. 19 (30 A) fuse in the under-hood fuse/relay box, and the No. 23 (7.5 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Reinstall the fuse(s), then go to step 2.
NO -
Replace the fuse(s). If the fuse continues to blow, locate and repair the short in the circuit between the auxiliary under-hood fuse/relay box and the PCM, the auxiliary 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 auxiliary under-hood fuse/relay box.�
2. Remove the radiator fan relay from the auxiliary under-hood relay box and test it Power Relay Test.
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 -
Repair an open in the wire between radiator fan relay 4P socket terminal No. 1 and 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 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 Service and Repair, and retest.
6. Check for continuity between radiator fan 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -
Go to step 7.
NO -
Check for an open in the wire between the radiator fan and body ground. If the wire is OK, check for poor ground at 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 auxiliary under-hood fuse/relay box and the radiator fan motor, the radiator fan motor and body ground (G201).�
NO -
Repair an open in the wire between radiator fan relay 4P socket terminal No. 2 and radiator fan motor 2P connector terminal No. 1.�
8. Turn the ignition switch to ON (II).
9. Measure the voltage between the fan control relay 5P socket terminal No. 5 and body ground.
Is there battery voltage?
YES -
Go to step 10.
NO -
Repair an open in the wire between the fan control relay and the under-dash fuse relay box.�
10. Measure voltage between radiator fan relay 4P socket terminal No. 4 and the body ground.
Is there battery voltage?
YES -
Go to step 11.
NO -
Repair an open in the wire between the radiator fan relay 4P socket terminal No. 4 and the under-dash fuse/relay box.�
11. Turn the ignition switch to LOCK (0).
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. 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.
16. Disconnect PCM connector A (49P).
17. Check for continuity between PCM connector A terminal No. 5 and the radiator fan relay 4P socket terminal No. 3.
Is there continuity?
YES -
Check for loose wires or poor connections at PCM connector A (49P). If the connections are good, substitute a known-good PCM, and recheck. If the symptom/indication goes away, replace the original PCM Service and Repair.�
NO -
Repair an open in the wire between the PCM and radiator fan relay 4P socket terminal No.3.�