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
- If A/C refrigerant pressure is abnormal, the radiator fans are controlled based on engine coolant temperature. Heating and A/C System Description (Without Climate Control)
1. Check the No. 20 (30 A) fuse in the under-hood fuse/relay box, and the No. 30 (10 A) fuse in the 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, check for a short in the No. 20 (30 A) and No. 30 (10 A) fuse circuits.
2. Remove the A/C condenser fan relay from the auxiliary under-hood fuse/relay box, and test it. Power Relay Test
Is the relay OK?
YES - Go to step 3.
NO - Replace the A/C condenser fan relay.
3. Connect the HDS to the DLC. How to Troubleshoot the Heating and A/C Systems
4. Turn the ignition switch to ON (II).
5. Turn on the A/C on the HVAC control unit.
6. Check the FAN LOW CTRL in the PGM-FI Data List with the HDS.
Is the FAN LOW CTRL on?
YES - Go to step 7.
NO - Substitute a known-good PCM, Initial Inspection and Diagnostic Overview and recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM. Service and Repair
7. Measure the voltage between the A/C condenser fan relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 8.
NO - Repair open in the wire between the No. 20 (30 A) fuse in the auxiliary under-hood fuse/relay box and the A/C condenser fan relay. If wire is OK, replace the under-hood fuse/relay box.
8. Connect A/C condenser fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.
Do the A/C condenser and radiator fans run on LOW?
YES - Go to step 9.
NO - Go to step 18.
9. Disconnect the jumper wire.
10. Turn the ignition switch to ON (II).
11. Measure the voltage between A/C condenser fan relay 4P socket terminal No. 4 and body ground.
Is there battery voltage?
YES - Go to step 12.
NO - Go to step 39.
12. Turn the ignition switch to LOCK (0).
13. Reinstall the A/C condenser fan relay.
14. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
15. Disconnect PCM connector A (49P).
16. Connect the PCM connector A (49P) terminal No. 4 to body ground with a jumper wire.
17. 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 PCM connector A (49P) No. 4 terminal. If the connections are good, substitute a known-good PCM, Initial Inspection and Diagnostic Overview and recheck. If the symptom/indication goes away, replace the original PCM. Service and Repair
NO - Repair open in the wire between the A/C condenser fan relay and the PCM.
18. Disconnect the jumper wire.
19. Reinstall the A/C condenser fan relay.
20. Disconnect the A/C condenser fan 2P connector.
21. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
22. Measure the voltage between A/C condenser fan 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 23.
NO - Repair open in the wire between the A/C condenser fan relay and the A/C condenser fan.
23. Turn the ignition switch to LOCK (0).
24. Reconnect the A/C condenser fan 2P connector.
25. Connect the A/C condenser fan 2P connector terminal No. 1 to body ground with a jumper wire.
26. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
Does the A/C condenser fan run at high speed?
YES - Go to step 27.
NO - Replace the A/C condenser fan motor.. Service and Repair
27. Turn the ignition switch to LOCK (0).
28. Disconnect the jumper wire.
29. Remove the fan control relay from the auxiliary under-hood relay box, and test it. Power Relay Test
Is the relay OK?
YES - Go to step 30.
NO - Replace the fan control relay.
30. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
31. Measure the voltage between fan control relay 5P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 32.
NO - Repair open in the wire between the A/C condenser fan and the fan control relay.
32. Turn the ignition switch to LOCK (0).
33. Reinstall the fan control relay.
34. Disconnect the radiator fan 2P connector.
35. Turn the ignition switch to ON (II), then set the A/C button and fan control button ON.
36. Measure the voltage between radiator fan 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 37.
NO - Repair open in the wire between the fan control relay and the radiator fan.
37. Turn the ignition switch to LOCK (0).
38. Check for continuity between radiator fan 2P connector terminal No. 1 and body ground.
Is there continuity?
YES - Replace the radiator fan motor.
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.
39. Turn the ignition switch to LOCK (0).
40. Remove A/C diode A from right engine compartment wire harness.
41. Using the diode setting on a DVOM, check for current flow in both directions between the A/C diode A terminals No. 1 and No. 2.
Is there current flow in only one direction?
YES - Go to step 42.
NO - Replace A/C diode A.
42. Turn the ignition switch to ON (II).
43. Measure the voltage between A/C diode 4P socket terminal No. 2 and body ground.
Is there battery voltage?
YES - Repair open in the wire between A/C diode A and the A/C condenser fan relay.
NO - Repair open in the wire between the No. 30 (10 A) fuse in the under-dash fuse/relay box and A/C diode A.
