Diesel Data: Automotive Repair

A/C Condenser Fan High Speed Circuit Troubleshooting




A/C Condenser Fan High Speed Circuit Troubleshooting

NOTE:

- Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the symptom troubleshooting index.
- Before doing any symptom troubleshooting, check for PGM-FI DTCs Initial Inspection and Diagnostic Overview.

1. Check the No. A4 (7.5 A) fuse and the No. A6 (20 A) fuse in the under-hood fuse/relay box.

Are the fuses OK?

YES -

Go to step 2.

NO -

Replace the fuse(s), and recheck. If fuse(s) blow again, check for a short in the No. A4 (7.5 A) fuse and/or the No. A6 (20 A) fuse circuit(s).

2. Jump the SCS line with the HDS.

NOTE: This step must be done to protect the PCM from damage.

3. Disconnect PCM connector A (49P).

4. Turn the ignition switch to ON (II).

5. Measure the voltage between PCM connector A (49P) terminal No. 45 and body ground.





Is there battery voltage?

YES -

Go to step 6.

NO -

Repair an open in the wire between the under-hood fuse/relay box and the PCM. If the wire is OK, replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.

6. Set the air conditioning button and fun control dial to off, then turn the ignition switch to LOCK (0).

7. Connect PCM connector A (49P) terminals No. 44, No. 45, and No. 49 to body ground with jumper wires.






8. Turn the ignition switch to ON (II).

Do the A/C condenser and the radiator fans run on high?

YES -

Check for loose wires or poor connections at PCM connector A (49P) . If the connections are good, substitute a known-good PCM, and recheck. If the symptom/indication goes away, replace the original PCM Service and Repair.

NO -

Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.