Defroster/defogger/hvac System problems of the 2025 GMC Sierra 1500

The contact owns a 2025 GMC Sierra 1500. The contact stated that while the defroster was activated to clear the windshield, the blower vents on the passenger’s side started making an abnormal hissing sound, and air produced by the blower motor decreased and was inadequate to clear the windshield. There was no warning light illuminated. The contact stated that the failure occurred while there was light snow covering the hood and on the outside vents underneath the windshield. The contact had taken the vehicle to a local dealer several times, and the dealer was unable to duplicate the failure. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 3,000.