[Shyguy]

Originally Posted by domeier

If'n I wuz you, I'd start troubleshooting at the turn signal switch and work my way out from there.

Purple in, is power from the turn signal flasher relay
Black/White in, is power from the stop lamp switch
Brown in, is power from the hazard flasher relay
All grounds are made after the lamp elements
Turn indicators in dash are powered off the front turn lamps

Left turn:
Purple in to switch goes to Black/yellow out (left brake/turn lamp)
Purple in to switch goes to Black/Blue out (left front turn lamp)
Black/White in to switch goes to Green out (right brake/turn lamp)

Right turn:
Purple in to switch goes to Green out (right brake/turn lamp)
Purple in to switch goes to Blue out (right front turn lamp)
Black/White in to switch goes to Black Yellow out (left brake/turn lamp)

No turn:
Black/White in to switch goes to Black/Yellow out (left brake/turn lamp)
Black/White in to switch goes to Green out (right brake/turn lamp)

I just went through something similar to your problem, and it took me a little while to finger out how the switch is supposed to work. Because the turn and brake lamp elements are shared, the switch is a bit complex. My switch was shot. Only lasted 42 years...

Thank you for posting this, it will help me fix the turn signal/brake light problem I have with the '67 swb stepper.