one dim tail light 1965 coup

Is the housing rusty? Or not as reflective as the "good" side? I was suprised with the difference when I replaced my housings... and painted them with a bright white for a quick fix

Is your lense a scratched/clouded up original? New reproductions do make a difference...

If the above don't apply or work, check the wiring with a dvm, and clean your grounds
 
Actually its pretty weird. I learned today with the flashers on the right (passenger) is dim, with the headlights on no flasher at all on the right, with the brakes on the left is bright, the right is dim, with the lights on the left is dim and the right is bright.

Any ideas would be greatly appreciated.
 
Tail Lamp problems

1) Take some steel wool and clean the contacts in both bulb sockets. Clean the sides of the socket so that it's bright.
2) Trace the wires in the tail light circuit that goes to ground. I think it goes to the brace at the fuel filler neck.
3) As said before, brighten up the bulb housing with some steel wool or even some high temp white or silver paint.
4) New lenses definately help.
5) Install a new flasher.
 
Did you try swapping bulbs?

Check voltage at the right tail light black wire to bare metal ground...It should have 12 v only when the lights are on.

Check voltage at the right tail light orange/blue wire to bare metal ground...It should have 12 v only when the Brakes are on.

By your description, it sounds like the black and orange/blue wires are reversed.

Has the socket, turn signal or hazard switch been changed?

I didn't know flashers were an option in '65. :shrug: