tismark

GMC Dealer advisor told me that 2014-2018 models do not completely close off the outside air coming in by design. The thought is that the AC/Defrost won't tend to build up mold inside the AC unit, at least not as fast as some previous designs. Ideally the User should turn off the outside air in feature before turning off the vehicle so the AC can have some fresh air to help prevent the mold smell issue on all models and doing this manually will help to keep all models cleaner inside.