im having the same no dash lights issue with my 71 dart.I thought i was having a ground problem,but putting an extra ground didnt make a difference.Do the switches go bad on just the instrument light output?
At the front of the headlight switch is a resistor coiled in a ceramic housing. The 3 amp fuse limits the current to protect the resistor. They often go bad anyway and often the only fault in the entire switch.
Two options... buy a new switch appox. 15.00 or
Take yours out and I'll show you a very simple way to bypass that resisitor resulting in bright as possible dash lights regardless where the knob is turned.
This jumper install has no effect on dome light or any thing else related.
