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, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine. Reading and Clearing Diagnostic Trouble Codes
- If A/C refrigerant pressure is abnormal, the radiator fans are controlled based on engine coolant temperature. Heating and A/C System Description (With A/C)
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 fuses blow again, check for a short in the No. 7 (20 A: M/T) or (30 A: A/T) and No. 36 (10 A) fuses circuit.
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, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine, Reading and Clearing Diagnostic Trouble Codes and retest. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
7. Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 8.
NO - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal/Installation
8. 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 9.
NO - Go to step 19.
9. Turn the ignition switch to LOCK (0).
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 38.
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 engine control module/powertrain control module (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, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine, Reading and Clearing Diagnostic Trouble Codes and recheck. If the symptom/indication goes away, replace the original ECM/PCM.
NO - Repair an open in the wire between the radiator fan relay and the ECM/PCM.
19. Turn the ignition switch to LOCK (0).
20. Disconnect the jumper wire.
21. Reinstall the radiator fan relay.
22. Disconnect the radiator fan motor 2P connector.
23. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
24. Measure the voltage between radiator fan motor 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 25.
NO - Repair an open in the wire between the radiator fan relay and the radiator fan motor.
25. Set the A/C button and fan control dial OFF, then turn the ignition switch to LOCK (0).
26. Reconnect the radiator fan motor 2P connector.
27. Connect radiator fan motor 2P connector terminals No. 1 to body ground with a jumper wire.
28. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
Does the radiator fan run?
YES - Go to step 29.
NO - Replace the radiator fan motor; R18A1 engine, Service and Repair K20Z3 engine. Service and Repair
29. Set the A/C button and fan control dial OFF, then turn the ignition switch to LOCK (0).
30. Disconnect the jumper wire.
31. 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 32.
NO - Replace the fan control relay.
32. Turn the ignition switch to ON (II), then set the A/C button and fan control dial ON.
33. Measure the voltage between fan control relay 5P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 34.
NO - Repair an open in the wire between the radiator fan motor and the fan control relay.
34. Set the A/C button and fan control dial OFF, then turn the ignition switch to LOCK (0).
35. Disconnect the A/C condenser fan motor 2P connector.
36. 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 37.
NO - Repair an open in the wire between the fan control relay and the A/C condenser fan motor.
37. 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 K20Z3 engine.
38. Turn the ignition switch to LOCK (0).
39. Remove A/C diode A from the under-hood fuse/relay box.
40. 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 41.
NO - Replace A/C diode A.
41. Turn the ignition switch to ON (II).
42. 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/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.
