Dash light issues
 

My 68 has developed an issue where the dash lights seem to dim and the turn signals will glow when the headlights are on. Also when this happens the fuel gauge reads empty. As soon as you turn the head lights off or turn the headlight switch fully clockwise (shutting off the dash lights), everthing returns to normal including the fuel indicator. The clock also works just fine and the headlights, etc., are unaffected.
After looking at the wiring diagram I cannot see any direct connection between the fuel gauge and the dash lighting. I guess if some thing could shorting out the fuel gauge, but it is not clear to me how.
Any idea?
Thanks,
Bill

It sounds like a ground issue, check the grounding wire behind the right headlight...also the ground from the body to motor that should be by the starter...at least that is where the grounds are on a 69. It sounds like a grounding problem to me so check all of them.

Maybe the voltage regulator ?

Will check it all out.
Thanks again.
Bill

Forward light harness grounds, Ric mentioned this. On a 70 there are grounds on both sides by the headlights. Also the voltage regulator ground, should be mounted on driver's side of rad support.

Don't think your chassis ground is correct Ric, not that it doesn't work. Chassis ground to battery should be through a short pigtail off the negative battery post to the passenger side fender. Engine ground is from battery to cylinder head or block.

Removed and cleaned all the ground connections in the engine compartment but it was not until I got under the dash that the real issue surfaced. Seems the ground was not good to the dash. Added a new ground and all is fine. I hate chasing electrical problems.
Thanks all for you advice.

Glad you found it...now you have all your grounds cleaned and in good working order and you know where they are now...so all is good.

Bw396ss, I have the exact same problem on my 70 SS. Where is the dash ground?

I must do mine when I replace the printed circuit.