Q: AC only blows hot air

Hello. We will be happy to assist! To diagnose an AC concern, I first suggest checking the refrigerant levels as it is the most vital component to the health of the AC system. Then, a technician should attempt directly switching on components from the Constant Control Relay Module controls, such as the cooling fan and AC compressor. If the components work fine when directly powered, then there may be an issue with the circuit of the AC system, or the Constant Control Relay Module may need to be replaced; the sensors in them are known to fail on your particular vehicle. Please keep in mind that the Federal Government mandates that all AC repairs be performed by an EPA-certified technician. A great way to find such technicians in your area is through "YourMechanic". They can send an EPA-certified technician to your Mustang’s location to inspect your AC system, and recommend the best path to repair.