meansam,
I have led's tail/brake lights on my 66, the brake lights would work as well as the turn signals on both sides, until I turned on the headlights. I would lose one (Not necessarily the same one) brake lights when applied. The turn signals would still work properly. Turned out it was a ground problem, following the circuit back thru the front lamps. I added ground straps everywhere, engine to body,(I forgot to replace) engine to frame, frame to bed. Seemed to take care of my problem
