I have been given a somewhat complete fresh air heater for my '50 3100, and I am wondering if what I have is complete or semi-complete. What I have is the housing with the motor and fan, defroster ports, a power switch and heater core. I have looked at the factory accessory installation manual and it shows a heat control valve plumbed into the system. Is that really necessary, or can I run the hoses with a shut-off valve at the thermostat housing? This truck never had a heater installed, and I have not been around either version of the factory heaters to know just what is needed.
