Therapy,
The first thing I would do is get a good battery instead of the battery charger. You may not be getting enough amps. to run the resister and motor.
The coil on the back of the heater switch I believe is the old rheostat that was used.
I would opt. for using a relay instead.
Good Luck
Paul


Paul

When you do a good deed, get a receipt just incase HEAVEN is
like....the IRS