Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting
Radiator and A/C Condenser Fan Low Speed Circuit TroubleshootingNOTE:
- 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, R18A1 engine, K20Z3 engine.
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 fuses, 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.
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 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.
7. Measure the voltage between the 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.
8. Connect the 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 18.
9. Disconnect the jumper wire.
10. Turn the ignition switch ON (II).
11. Measure the voltage between the radiator fan relay 4P socket terminal No.3 and body ground.
Is there battery voltage?
YES - Go to step 12.
NO - Go to step 36.
12. Turn the ignition switch OFF.
13. Reinstall the radiator fan relay.
14. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the engine control module (ECM)/powertrain control module (PCM) from damage.
15. Disconnect ECM/PCM connector A (44P).
16. Connect the ECM/PCM connector A (44P) terminal No.4 to body ground with a jumper wire.
17. Turn the ignition switch ON (II).
Do the Ale 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, and recheck. If the symptom/indication goes away, replace the original ECM/PCM, R18A1 engine, K20Z3 engine.
NO - Repair open in the wire between the radiator fan relay and the ECM/PCM.
18. Disconnect the jumper wire.
19. Reinstall the radiator fan relay.
20. Disconnect the radiator fan 2P connector.
21. Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.
22. Measure the voltage between the radiator 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 radiator fan relay and the radiator fan.
23. Set the A/C button and fan control dial OFF, then turn the ignition switch OFF.
24. Reconnect the radiator fan 2P connector.
25. Connect the radiator fan 2P connector terminal No.1 to body ground with a jumper wire.
26. Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.
Does the radiator fan run?
YES - Go to step 27.
NO - Replace the radiator fan motor, R18A1 engine, K20Z3 engine.
27. Set the A/C button and fan control dial OFF,then turn the ignition switch OFF.
28. Disconnect the jumper wire.
29. Remove the fan control relay from the under-hood relay box, and test it.
Is the relay OK?
YES - Go to step 30.
NO - Replace the fan control relay.
30. Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.
31. Measure the voltage between the 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 radiator fan and the fan control relay.
32. Set the A/C button and fan control dial OFF,then turn the ignition switch OFF.
33. Disconnect the A/C condenser fan 2P connector.
34. Check for continuity between the fan control relay 5P socket terminal No.4 and the A/C condenser fan 2P connector terminal No.2.
Is there continuity?
YES - Go to step 35.
NO - Repair open in the wire between the fan control relay and the A/C condenser fan.
35. Check for continuity between the A/C condenser fan 2P connector terminal No.1 and body ground.
Is there continuity?
YES - Replace the A/C condenser fan motor, R18A1 engine, K20Z3 engine.
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 ground at G301.
36. Turn the ignition switch OFF.
37. Remove A/C diode A from the under-hood fuse/relay box.
38. 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 39.
NO - Replace A/C diode A.
39. Turn the ignition switch ON (II).
40. Measure the voltage between the A/C diode A 2P socket terminal No.2 and body ground.
Is there battery voltage?
YES - Replace the under-hood fuse/relay box.
NO - Repair open in the wire between the No. 36 (10 A) fuse in the under-dash fuse/relay box and A/C diode A.