P0645

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 vehicle. A P0645 code in your Mustang indicates an issue with the A/C clutch relay control circuit. It means the system is having trouble engaging the A/C compressor, possibly due to a faulty relay, wiring issues, or even a problem with the A/C clutch itself. The quickest check would be to visually inspect the clutch and associated wiring for damage. If all seems to be in order, the next step would be to locate your compressor clutch relay and swap it for a known good one. Beyond that, this issue could get pretty complex, and it may be best to find a trusted repair shop to dig a little deeper. 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!