Dash lights don't work

[69GT]

Ever since I got my 67 GTX the dash lighting has't worked. I have checked all of the bulbs (which are good), checked the fuse (good), tried a different headlight switch (used so I guess it could be bad as well but I don't think so) to no avail. I have also run a separate ground wire from the switch to the dash frame just in case it didn't have a sufficient ground. The switch does turn the headlights and dome light off and on properly. I have aftermarket gauges that are wired to the instrument panel lamp terminal in the fuse box. They don't light either nor does the light on the column mounted shift indicator or the radio. I know I could try a new switch but before I buy one I would appreciate any suggestions as to what else I might check that might be to blame.

 

[Demonic]

You have a DC voltmeter? Time to verify the switch and follow the circuit. Sounds like issues in the fusebox if the power tap there has issues. Even the cheap meters at harbor freight seem to work well enough, as much as I dislike buying Chinese crap.

 

[Pete Kaczmarski]

Start simple...many of these switches are dirty. Purchase a can of electrical cleaner spray. Get one with the nozzle extension and spray liberally into the switch with the four inch extension placed onto the nozzle. Do not use WD40 or the like as it could cause an electrical fire. About ten years ago my friend did that on his power seat switch and later that day the car was filled with smoke as it shorted out the switch.

 

[Coronutcase]

Could be the wiring that goes into the fuse box, or could be a bad circuit board. Classic Industries sells new ones that are "modernized" to eliminate the usual problems.

 

[Shorthorse]

http://www.mymopar.com/downloads/1967/67BelvedereA.JPG
http://www.mymopar.com/downloads/1967/67BelvedereB.JPG

Unswitched power is fed to the light switch to terminal B1, black tracer wire. When light switch is activated power is supplied to the IN terminal, tan wire. Inside the switch that circuit goes through the rheostat to allow the dimming function. The tan wire output feeds battery to the light fuse. The output from the fuse, orange wire, feeds the lamps. As Demonic said, get a voltmeter. Turn the switch on and check for battery on the lamp fuse, both sides. If none, start looking backwards (tan wire) toward the switch. If there is battery, start looking toward the lamps (orange wire).
Don't pay attention to the dome/courtesy lamps. They are on a different fuse and work via a switched ground not a switched battery like the dash lights.