Just hooked up the battery yesterday as I'm completing the resto of a 70 Abody. Everything works well except for the RH turn signal and brake light. This is what I have found so far:

Started at the back - no power on the green wire at the lamp, trunk connector, body harness to dash harness connector, or turn signal connector to dash harness connector.

RH turn signal bulb in dash comes on and stays on when I use the turn signal.

LH side works fine.

I'm thinking (groan) it is in the wiring coming out if the turn signal switch or the switch itself. Any other possibilities before I take the wheel, adaptor, lock plate off?

MDechanic-hope you are online!!

 

Just had the same problem on the same light on my 69 cutlass turned out to be a bad ground at the light. funny thing is the running light was working. Gave it a good ground and everything came on.

 

Joe, I don't know if it will help or hurt but I bought a 70 Supreme beater a few years
back and had the same problem. I separated and cleaned the firewall side of the fuse box
harness and it went to working. I know that yours is all refurbished, but this worked for me.
Good luck with it it, electrical gremlins can be tough at times. Hopefully it will be somewhat of a painless fix.

 

Update - was tossing and turning, and remembered I was missing a fuse from the fuse box. Plugged in the AGC 25 and voila! With the key on, turn signals work on both sides. (Which is really confusing because the LH ones were working before I plugged the fuse in).

On the negative side now, I don't have brake lights now! I had the LH brake light working before I plugged the fuse in, and now I also have the LH turn signal bulb in the dash continuously lit. Also, the front LH turn signal bulb seems a lot dimmer than the RH side. Sounds like a weird grounding issue now??

I know this all seems strange, but it is exactly as it has gone. Maybe check the front turn signal ground? Is it to the bumper directly from the housing?