I am trying to install a Clayton Heater but it keeps blowing the fuse. It runs on a battery charger supply but when I try to run it off a fuse supply it blows. there are 2 wires, I ran 1 to neg earth and 1 to a fuse supply. I have tried a rheostat switch and and ordinary ps7 push/pull. 5.10.15.30 fuses all blow. changed the motor both run freely until I connect in the car, anybody can help. Steve