[EDIT]

Is this a 6 Volt truck with a 12 Volt inverter installed somewhere? If so, then:

You presently have the coil resistor for your 12 volt coil wired to a 6 volt source (the starter terminal).



Last edited by Norcal Dave; 05/23/2017 4:34 PM.

~ Dave
1950 Chevrolet 3600 3/4-ton with 261 engine & T5 Transmission