Hi, so this is what's happening.
Heater is on auto set at 22 degrees and works well most of the time. It does well to heat the car up and keep it at comfortable temperature. However sometimes during longer trips (40+ mins), mostly when cruising on a highway the heater starts blowing cool air. Cranking the heat up to say 25 degrees switches it back to warm air.
My guess is that something might heat up in the vicinity of the sensor and make it think it's warmer in the car than it actually is. Any ideas on troubleshooting/fixes are welcome.