When your AC works it's a beautiful thing, however, when it begins to blow warm it can be frustrating. For one thing, an AC system is a complex system within a vehicle and requires special tools and environmental precautions when working on them. AC systems are a closed system meaning it doesn't need routine fluid top-offs. So, if you are experiencing warm air it's an indication of a bigger problem. We've identified 3 common reasons why a vehicle's AC is blowing warm or hot.
Unlike oil leaks, refrigerants can be tricky to spot. Refrigerant is a gas so doesn’t leave puddles or obvious signs of leak. Also, the fittings and gaskets are small so it takes a trained eye to find any irregularities.
The compressor is the mothership of your AC system. It’s a complicated mechanical part that is responsible for circulating refrigerant. Like many parts on a vehicle they fail over time. Some things you can do to prolong the life of the compressor is to run the AC every month for at least 10 minutes. This is pretty easy to do in most modern vehicles as the compressor also drives the defrost.
The AC System is full of wires, sensor, relays, and pressure switches. If any of these things are making a poor connection or failing it can cause the AC to blow warm air. Without the proper equipment or, more importantly, an experienced professional diagnosing the problem these issues are difficult to isolate.