Drove truck this weekend. A/C worked great, until I turned it on high. The light on the a/c button goes out, blower still works but does not blow cold. Go back to medium or low, and everything works great. Only high causes the problem. Any thoughts?
Could be the switch? With the selector below the high setting, the power for the blower fan runs thru a resistor register, and the high setting runs a full 12vdc from the power source. You'll have to see how it's wired up (maybe by purchasing the wiring book, or persuading one of the members who have to post it).
Yeah, buy the spiral bound manual. It has all the wiring diagrams in it. I bet it is just a bad switch if the a/c works at other settings.