Why does my 2019 GMC Yukon XL AC only blows cold when the vehicle is in motion.

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. So sorry to hear you're having trouble with your Yukon. When your AC blows cold only when the vehicle is in motion, it's often due to insufficient airflow over the condenser. The condenser needs airflow to cool the refrigerant effectively. When the car is moving, the airflow is provided by the vehicle's movement. But when you're stopped, the fan should be providing that airflow. If the AC blows warm air at a stop, the issue could be with the condenser fan. It might not be running at full speed or at all, leading to poor cooling performance. Another possibility is low refrigerant, which can cause the AC to struggle at lower engine speeds. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!