Radiator And A/C Condenser Fan Low Speed Circuit Troubleshooting (With A/C)
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.
- Before performing symptom troubleshooting, check for powertrain DTCs; R18A1 engine Initial Inspection and Diagnostic Overview, K20Z3 engine Initial Inspection and Diagnostic Overview.
- If A/C refrigerant pressure is abnormal, the radiator fans are controlled based on engine coolant temperature.
1. Check the No. 7 (20 A: M/T) or (30 A: A/T) fuse in the under-hood fuse/relay box, and the No. 36 (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) blows again, check for a short in the No. 7 (20 A: M/T) or (30 A: A/T) fuse and the No. 36 (10 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. Connect the HDS to the DLC.
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 ECM/PCM; R18A1 engine, K20Z3 engine, and retest. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM; R18A1 engine , K20Z3 engine Service and Repair.�
7. Turn the ignition switch to LOCK (0).
8. Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 9.
NO -
Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.�
9. Connect radiator 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 10.
NO -
Go to step 19.
10. Disconnect the jumper wire.
11. Turn the ignition switch to ON (II).
12. Measure the voltage between radiator fan relay 4P socket terminal No. 3 and body ground.
Is there battery voltage?
YES -
Go to step 13.
NO -
Go to step 34.
13. Turn the ignition switch to LOCK (0).
14. Reinstall the radiator fan relay.
15. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the ECM/PCM from damage.
16. Disconnect ECM/PCM connector A (44P).
17. Connect ECM/PCM connector A (44P) terminal No. 4 to body ground with a jumper wire.
18. 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 (44P) terminal No. 4. If the connections are good, substitute a known-good ECM/PCM; R18A1 engine, K20Z3 engine, and recheck. If the symptom/indication goes away, replace the original ECM/PCM; R18A1 engine , K20Z3 engine Service and Repair.�
NO -
Repair an open in the wire between the radiator fan relay and the ECM/PCM.�
19. Disconnect the jumper wire.
20. Reinstall the radiator fan relay.
21. Disconnect the radiator fan motor 2P connector.
22. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
23. Measure the voltage between radiator fan motor 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Go to step 24.
NO -
Repair an open in the wire between the radiator fan relay and the radiator fan motor.�
24. Set the A/C button and fan control dial OFF, then turn the ignition switch to LOCK (0).
25. Test the radiator fan motor; R18A1 engine Testing and Inspection, K20Z3 engine Testing and Inspection.
Is the radiator fan motor OK?
YES -
Go to step 26.
NO -
Replace the radiator fan motor; R18A1 engine Service and Repair, K20Z3 engine Service and Repair.�
26. Reconnect the radiator fan motor 2P connector.
27. Remove the fan control relay from the under-hood relay box, and test it Testing and Inspection.
Is the relay OK?
YES -
Go to step 28.
NO -
Replace the fan control relay.�
28. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
29. Measure the voltage between fan control relay 5P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 30.
NO -
Repair an open in the wire between the radiator fan motor and the fan control relay.�
30. Set the A/C button and fan control dial OFF, then turn the ignition switch to LOCK (0).
31. Disconnect the A/C condenser fan motor 2P connector.
32. Check for continuity between fan control relay 5P socket terminal No. 4 and A/C condenser fan motor 2P connector terminal No. 2.
Is there continuity?
YES -
Go to step 33.
NO -
Repair an open in the wire between the fan control relay and the A/C condenser fan motor.�
33. Check for continuity between A/C condenser fan motor 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -
Replace the A/C condenser fan motor; R18A1 engine Service and Repair, K20Z3 engine Service and Repair.�
NO -
Check for an open in the wire between the A/C condenser fan and body ground. If the wire is OK, check for poor body ground at G301; R18A1 engine, K20Z3 engine.�
34. Turn the ignition switch to LOCK (0).
35. Remove A/C diode A from the under-hood fuse/relay box.
36. Using the diode setting () on a DVOM, check for current flow in both directions between A/C diode A terminals No. 1 and No. 2.
Is there current flow in only one direction?
YES -
Go to step 37.
NO -
Replace A/C diode A.�
37. Turn the ignition switch to ON (II).
38. Measure the voltage between A/C diode A 2P socket 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. 36 (10 A) fuse in the under-dash fuse/relay box and A/C diode A.�