GMC Sierra 2500 HD AC blowing cold air through defrost vents causing windshield fogging on GMC Sierra 2500 HD

Some GMC Sierra 2500 HD owners report experiencing issues with their AC blowing cold air through the defrost vents, which can lead to windshield fogging. Common causes of this problem include low refrigerant levels, which can result in inefficient cooling and discomfort in the cabin. Additionally, a faulty compressor may cause the AC system to malfunction, leading to cold air being directed only through the defrost vents. Clogged condensers can further hinder cooling efficiency, resulting in warm or hot air that contributes to fogging. Lastly, issues with the mode door actuator can prevent proper air circulation, causing air to be funneled exclusively through the defrost vents. To resolve these concerns, it is advisable for owners to check these potential issues and seek professional assistance for accurate diagnosis and repair.