air controls?

wondering if anyone has an idea of why my air speed control on works on high for the heat and air?

This is indicative of a bad blower resistor. There are three resistance coils which decrease the voltage to the blower fan for speeds 1, 2, and 3, but high is a straight shot.

These are available new for about $45 at parts stores, the assembly is located on the top of the air box (remove the glove box and its door for access). There are two wire connectors; after those are removed, just 2 Phillips screws. I posted a How To topic in the project section about a week ago, with resistance values for each coil.