Diesel Data: Automotive Repair

Heating and A/C




Driver's and passenger's side vent temperatures vary by more than 20 °F (11 °C)

Driver's and passenger's side vent temperatures vary by more than 20 °F (11 °C)

Probable causes: The recirculation control door or the air mix door is malfunctioning

Do the following troubleshooting:

Recirculation control motor circuit troubleshooting Recirculation Control Motor Replacement

Front air mix control motor test Front Air Mix Control Motor Test

Also check for

HVAC DTCs How to Troubleshoot the Heating and A/C Systems

Also check for

Poor or loose connections at the terminals