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 symptom troubleshooting, check for powertrain DTCs.

1. Check the No. 6 (30 A) fuse and the No. 15 (7.5 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 the fuse(s) blow again, check for a short in the No. 6 (30 A) and the No. 15 (7.5 A) fuse(s) circuit.�

2. Remove the A/C condenser 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 A/C condenser fan relay.�

3. Measure the voltage between A/C condenser fan relay 4P socket terminal No. 1 and body ground.





Is there battery voltage?

YES -

Go to step 4.

NO -

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

4. Connect A/C condenser fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.





Does the A/C condenser fan run on high?

YES -

Go to step 5.

NO -

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

5. Disconnect the jumper wire.

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

7. 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 8.

NO -

Go to step 14.

8. Turn the ignition switch to LOCK (0).

9. Reinstall the A/C condenser fan relay.

10. Jump the SCS line with the HDS.

NOTE: This step must be done to protect the powertrain control module (PCM) from damage.

11. Disconnect PCM connector A (49P).

12. Connect PCM connector A (49P) terminals No. 4, No. 5 and No. 40 to body ground with a jumper wire.






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

Does the A/C condenser fan run on high?

YES -

Check for loose wires or poor connections at PCM connector A (49P) terminals No. 5 and No. 40. 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 -

Repair an open in the wire between the A/C condenser fan relay and the PCM.�

14. Remove A/C diode B from the under-hood fuse/ relay box.

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

16. Measure the voltage between A/C diode B 2P socket terminal No. 2 and body ground.





Is there battery voltage?

YES -

Go to step 17.

NO -

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

17. Using the diode setting () on a DVOM, check for current flow in both directions between A/C diode B terminals No. 1 and No. 2.





Is there current flow in only one direction?

YES -

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

NO -

Replace A/C diode B.�