Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting
Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting
NOTE:
- Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the symptom troubleshooting index.
- Before performing symptom troubleshooting, check for powertrain DTCs. Initial Inspection and Diagnostic Overview
1. Check the No. 3-6 (MAIN FAN MTR) (30 A) fuse in the under-hood fuse/relay box, and the No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box.
Are you fuses OK?
YES - Go to step 2.
NO - Replace the fuse(s), and recheck. If the fuse(s) blow again, check for a short in the No. 3-6 (MAIN FAN MTR) (30 A) fuse and the No. 16 (7.5 A) fuse circuits.
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 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 the radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.
Do the radiator and A/C condenser fans run on low?
YES - Go to step 5.
NO - Go to step 14.
5. Disconnect the jumper wire.
6. Turn the ignition switch to ON (II).
7. Measure the voltage between the radiator fan relay 4P socket terminal No. 4 and body ground.
Is there battery voltage?
YES - Go to step 8.
NO - Go to step 34.
8. Turn the ignition switch to LOCK (0).
9. Reinstall the radiator fan relay.
10. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the engine control module/powertrain control module (ECM/PCM) from damage.
11. Disconnect ECM/PCM connector A (49P).
12. Connect the ECM/PCM connector A (49P) terminal No. 5 to body ground with a jumper.
13. Turn the ignition switch to ON (II).
Do the A/C condenser and radiator fans run on low?
YES - Check for loose wires or poor connections at ECM/PCM connector A (49P) terminal No. 5. If connection are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM. ECM/PCM Replacement (A/T)
NO - Repair an open in the wire between the radiator fan relay and the ECM/PCM.
14. Disconnect the jumper wire.
15. Reinstall the radiator fan relay.
16. Disconnect the radiator fan motor 2P connector.
17. Turn the ignition switch to ON (II), then set the A/C button and fan control button ON.
18. Measure the voltage between the radiator fan motor 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 19.
NO - Repair an open in the wire between the radiator fan relay and the radiator fan motor.
19. Set the A/C button and fan control button OFF, then turn the ignition switch to LOCK (0).
20. Reconnect the radiator fan motor 2P connector.
21. Connect the radiator fan motor 2P connector terminal No. 1 to body ground with a jumper wire.
22. Turn the ignition switch to ON (II), then set the A/C button and fan control button ON.
Does the radiator fan run at high speed?
YES - Go to step 23.
NO - Replace the radiator fan motor. Service and Repair
23. Set the A/C button and fan control button OFF, then turn the ignition switch to LOCK (0).
24. Disconnect the jumper wire.
25. Remove the relay circuit board Drivers Under-Dash Fuse/Relay Box (MICU) Removal and Installation (USA Models) from the under-hood fuse/relay box, and test the fan control relay. Testing and Inspection
Is the relay OK?
YES - Go to step 26.
NO - Replace the relay circuit board.
26. Reinstall the relay circuit board.
27. Disconnect under-hood fuse/relay box connector B (14P) and the radiator fan motor 2P connector.
28. Check for continuity between under-hood fuse/relay box connector B (14P) terminal No. 11 and the radiator fan motor 2P connector terminal No. 1.
Is there continuity?
YES - Go to step 29.
NO - Repair an open in the wire between the under-hood fuse/relay box and the radiator fan motor.
29. Reconnect under-hood fuse/relay box connector B (14P) and the radiator fan motor 2P connector.
30. Disconnect the A/C condenser fan motor 2P connector.
31. Turn the ignition switch to ON (II), then set the A/C button and fan control button ON.
32. Measure the voltage between the A/C condenser fan motor 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 33.
NO - Repair an open in the wire between the under-hood fuse/relay box and the A/C condenser fan motor.
33. Measure the voltage between the A/C condenser fan motor 2P connector terminals No. 1 and No. 2.
Is there battery voltage?
YES - Replace the A/C condenser fan motor. Service and Repair
NO - Check for an open in the wire between the A/C condenser fan motor and body ground. If the wire is OK, check for poor ground at G301.
34. Turn the ignition switch to LOCK (0).
35. Remove the relay circuit board. Drivers Under-Dash Fuse/Relay Box (MICU) Removal and Installation (USA Models)
36. Using the diode setting on a DVOM, check for current flow in both directions between relay circuit board connector B (14P) terminals No. 2 and No. 10.
Is there current flow in only one direction?
YES - Go to step 37.
NO - Replace the relay circuit board.
37. Turn the ignition switch to ON (II).
38. Measure the voltage between under-hood fuse/relay box connector B (14P) terminal No. 2 and body ground.
Is there battery voltage?
YES - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal and Installation
NO - Repair an open in the wire between the No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box and under-hood fuse/relay box.
