All of a sudden, my upper heater switch (the one that says Off -> Heat -> Defrost) got stuck and would only move to the left (towards Off). I pulled the heater controls out far enough to spray in some WD-40, but that didnt work. Also, reaching in behind the switch and moving it from back there allowed me to move it pretty close to the Heat marker. This car is my daily driver, so I kinda need heat and defrost. Help!