hope I picked the right place to post this - I'm looking for advice with this problem on my '68....
I had the instrument cluster out of the car to fix a couple of unrelated issues. Everything was working fine prior to removal. On re-assembly I didn't have a left signal or high beam indicator. I'd had a hard time disconnecting the wiring harness plug when I took it apart so figured I'd maybe damaged the circuit board. When I took it apart again I found that the board was delaminated at the plug-in and 2 or 3 circuits would have crossed and probably shorted. I got a new circuit board and tested all the bulbs and fuses.
Back together and I still don't have a left signal or high beam indicator! Signals and high beam are working. I'm stumped. Am I overlooking something obvious?
I'm pretty sure the ground is ok but will double check for continuity. The ground wire Gary mentions runs from a terminal on the left of the tach down to the pedal mounting bracket assembly so that'll be easy to test. I'll dig out schematics to find the source for testing continuity to the proper terminals on the plug Carl, that's certainly worth checking too. I'm not a big believer in coincidences so gotta think the problem isn't with the new circuit board.
I will follow-up with these suggestions and update my post. Any other thoughts are appreciated.