Service VME - AC Control Head Inoperative or Blank Display - keywords battery control DIC fuse HVAC ice lock logic temperature up

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some dealers have noticed that the AC may be inoperative or the information on the AC control head is blank or incorrect.

Technicians should be reminded that in cases where the engine has been turned off for under three hours the exterior temperature display will read the last stored temperature. It may take a minute or two to update the temperature. This is normal condition and explained in SI document 906000

Additionally, cases have been noted where the DIC may display erroneous "Ice Possible" message on the DIC when temperatures are well above freezing. This has been noted in cars with very little mileage and it may be a faulty connection on the AC control head. Before replacing any AC control head, technicians should disconnect the battery and remove the three wiring connectors at the back of the AC control head. After removing the connections wait 60 seconds and reinstall the connectors and then reconnect the battery. Disconnecting the battery is critical as this will remove any residual electrical inputs in the AC circuits and allow the control head to reestablish contact with the BCM. No AC control head should be replaced with out completing this process first. These parts are currently on 100% part return and all parts are being tested when they are received at the WPC.

If your dealership encounters a AC control head that requires replacement and it is not corrected with this process, please contact Art Spong at 586-947-8890 before replacing the control head.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.