1965 Chevy C10 round knob, thrift air heater. pull knob with settings as you turn right: off, low, med, high A few months ago I had an electrical melt down in the engine compartment and behind the dash. I replaced harnesses, fixed burned up wires behind the instrument panel, put it all back together. I'm still chasing down where all the little light bulbs go. Now, the heater only works on high, and it blows strong as it ever did. If I turn it down to med or low, it goes off. My first thought is maybe I knocked something loose or didn't plug something back in... but on the back of the heater switch, I don't feel any exposed plugs, seems like everything is plugged in. Maybe the switch went kaput after all this time? I dunno. Is it possible to run it only on high because something is unplugged? I've been flipping through my shop manuals trying to find out what wires go to the heater switch, but haven't seen it yet in the wiring diagram, or I'm just missing it. Thought I'd ask you guys. Thanks. -Woog