Diesel Data: Automotive Repair

Radiator And A/C Condenser Fan Common Circuit Troubleshooting




Radiator and A/C Condenser Fan Common Circuit Troubleshooting

NOTE: Do not use this troubleshooting procedure if only one fan is inoperative, or the A/C compressor is inoperative. Refer to the symptom troubleshooting index.

1. Check the No. 1 (30 A) and No. 4 (20 A) fuses in the under-hood fuse/relay box, and the No. 14 (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 any of the fuses blows again, check for a short in the No. 1 (30 A), No. 4 (20 A), or No. 14 (10 A) fuse circuits.�

2. Remove the A/C condenser fan relay from the under-hood fuse/relay box.

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

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





Is there battery voltage?

YES -

Go to step 5.

NO -

Repair an open in the BLK/YEL wire between the No. 14 (10 A) fuse in the under-dash fuse/relay box and the radiator fan relay socket, and the A/C condenser fan relay socket.�

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

6. Reinstall the A/C condenser fan relay.

7. Make sure the A/C button is OFF.

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

9. Measure the voltage between ECM/PCM connector E (31P) terminal No. 12 and body ground with the ECM/PCM connectors connected.





Is there battery voltage?

YES -

Check for loose wires or poor connections at ECM/PCM connector E (31P). If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM ECM/PCM Replacement (A/T).�

NO -

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