Defect
On certain vehicles, the software programming in the Heating, Ventilation, Air Conditioning (HVAC) controller may allow a combination of numerous data inputs to temporarily overload the calculation capacity of the controller, resulting in incorrect signals to be transmitted to the heater case mode door. This may cause the mode door to move to unselected positions during heater operation until the controller recovers and returns to proper operation. Over time, this excessive movement may damage the mode door shaft. These conditions could affect defroster performance, resulting in delayed clearing of the windshield, which could compromise safe vehicle operation and increase the risk of a crash.
Safety Risk
No risk description available.
Remedy
Dealers will replace the HVAC controller assembly, inspect the mode-door shaft for possible damage, and repair the mode-door shaft if necessary.
