Denny,
I have a Johnny Cash truck. It is titled as a 53 but the Huck brakes and other small differences on the cab and chassis tells me that it is a 50, although the motor is a 53. When I got the truck it had a partial and badly done 12 volt conversion. It had a fresh air delux heater but the control valve and heater motor switch were missing and the motor was disconnected. I found a control valve and three heater switches at a junkyard. The valve and switch I'm using came from a 50 Chevy 1 ton. The other two switches came from a 51 and 53 GMC, but except for the color they were all the same. I rebuilt the control valve (you have to calibrate it for the off position when reassembling) and none of the three switches worked right. I had to disassemble all three switches to get a good one. I replaced the heater motor with a 12 volt motor. I hooked a battery charger to one side of the switch and the motor to the other side. I have three speeds. I ran the motor for over an hour at high speed and the switch never got warm. At the medium and low speeds the switch got warm from the resistor but not overly hot. My switch is the paddle type and is maroon with white lettering that says HEAT.
