HVAC Door Concerns DTCs B0228 B0413 B0433 B3779 B3782 - keywords a/c ac door mode temperature

This PI is being updated to add additional diagnostic help and models. Please discard PIT4058.

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

The GM HVAC Engineering Team is seeing an increase in front HVAC actuator warranty where the root cause is damage to the wiring harness. Engineering would like to understand more clearly how and where this HVAC harness is getting damaged, see the picture below for one common area. If you encounter a vehicle with this concern and the front HVAC wiring harness is damaged, Engineering would like to talk with you to get more information on how and where this is occurring. You can contact Ray Norton at 248-841-3773 to discuss the case in more detail. If you leave a message and do not hear back within 1 hour, do not hold the vehicle and continue with normal repairs.

If no harness damage is found and there is still a concern with an HVAC actuator, before replacing the actuator perform a reset of the front HVAC control head. To perform a reset remove the "HVAC BATT" fuse for one minute and reinstall. After the fuse has been reinstalled start the engine and allow to run for one minute without using the hvac controls. After one minute use the Tech 2 to perform a door relearn procedure by entering Body/ HVAC Control Module/ Special Functions/ Recalibrate All Motors. If the actuator begins to operate, no further repairs necessary. If the actuator still does not operate perform normal diagnostics. Thanks for your help.

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.