Diesel Data: Automotive Repair

Audio-HVAC Display Communication Line Circuit Troubleshooting




Audio-HVAC Display Communication Line Circuit Troubleshooting

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

2. Disconnect HVAC control unit connector A (24P) and audio-HVAC display unit 16P connector.

3. Check for continuity between the following terminals of HVAC control unit connector A (24P) and audio-HVAC display unit 16P connector.









Is there continuity?

YES -

Go to step 4.

NO -

Repair an open in the wire between the HVAC control unit and the audio-HVAC display unit.�

4. Check for continuity between body ground and HVAC control unit connector A (24P) terminals No. 11 and No. 12 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the HVAC control unit and the audio-HVAC display unit.�

NO -

Go to step 5.

5. Reconnect HVAC control unit connector A (24P).

6. Connect audio-HVAC display unit 16P connector terminals No. 11 and No. 12 with a jumper wire.






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

8. Press and hold the DEF button and FAN ON/OFF button.

Is the DEF button LED blinking?

YES -

Audio-HVAC display unit is faulty, replace the audio-HVAC display unit Audio-HVAC Display Unit Removal/Installation.�

NO -

HVAC control unit is faulty, replace the HVAC control unit HVAC Control Unit Removal/Installation.�