If wiring the switch down fixed the problem, then I wouldn't worry about fixing it. IIRC, the switch is made as part of the HVAC controls, on the later trackicks, so you have to replace that whole assembly, just to replace the switch....yeah, stupid, I know.
You might be able to take the switch apart, clean the contacts, put some dielectric grease on them, and reassemble and get the switch to work for a long time. If you do take the switch apart, be careful, there is a tiny ball and spring in there and they will go flying, if you aren't paying attention, when you open up the switch.