Heater circuit question
 

I currently have my interior apart on my 61 including the dash and centre console , I still have it wired to allow for basics such as starting etc but otherwise it is mostly disconnected .
Whilst playing with the radio I noticed an obnocious smell that horrible theres a wire getting hot somewhere . Turned out to be the back of the heater switch which has what appears to be a small coil / resistor ? attached to it presumably to govern the heater speeds .
Question :- should this be getting hot ? and if so why ? could it be there is no earth to the switch ?
Also there seems to be no heater shown on the wiring diagrams just a brown wire from heater switch to fuse box .
Hope its something simple
TIA
Mike .

Yes, the switch includes the resistance elements that control the blower speeds. The blower motor (oddly enough) is grounded through the sheath around the heater control cable, through the switch housing, to the die-cast console plate the switch is mounted to, and the console plate has a separate black ground wire screwed to the back side of it. Most guys run an extra separate ground wire from one of the heater blower motor flange screws to a good ground on the framework under the right side of the dash to provide a dedicated ground for the motor instead of depending on the flaky ground through the control cable. :thumbs:

thanks John , I also run an extra ground from the heater box just to be sure and it was all working just fine , I am just a little concerned as to why this resistor got so hot , any ideas ?
Mike .

The inside of that switch is pretty delicate, especially the fiber board with the resistor contacts on it; it may simply be dying of old age and deterioration. Mary Jo Rohner's husband rebuilds them, and Corvette Central is advertising a "coming soon" reproduction cable/switch assembly (NOS ones bring $300-$400 these days). :thumbs: