[Karl Wescott]

The switch is designed to ground through the dash. If paint, bondo, or rust has insulated the dash the circuit will not be completed.


Try removing the wire from the switch and shorting the wire to known ground, if things work its the switch or ground connection. Now, with the switch out of the dash clamp a wire to ground to the switch housing. Try the switch. If thing works its likely a ground problem, if not likely a switch problem.


If the switch is good then consider soldering a ground wire to the switch housing (making it a two terminal switch). A best practice "street rodders" use is to run a heavy gauge wire across the dash grounded on both sides, then connect ground on any switch or gauge to the ground wire.