The Stovebolt Site Forums The Shop Area The Electrical Bay Heater/Defrost Wiring

Hello all,

I'm at the end of a 12v conversion on my 3600 and I was wondering if anyone had a wiring diagram that included the heater/defrost motors in it? I have two variable switches and two motors in the unit itself. I haven't added in in-line resistors yet and that was next on my list, however the new 12v mechanical flasher socket seems to have a loose wire. When I wiggle it with the engine running, both heater motors turn on. This seems impossible since both switches for them are in the 'off' position, but that's what's happening. I just want to chase the heater wires back to make sure they are correct. I didn't have any issues like this with 6v, so this seems pretty odd to me.

Thanks!

The '48/'49 Chevy truck wiring diagram I just pulled from The Old Car Manual Project doesn't show the heater. Must have been an option.

Because of the "2 fan motor" heater/defroster you have I'm guessing your 12 volt conversion wiring system is aftermarket. Don't you have a diagram?

This might be a Canadian thing or dealer installed. I guess there won't be any diagrams. Would it be best to wire this to the aux connector on the light switch?

That's what I would do. Tie the feed for the two switches to the aux terminal of the ignition switch.