How would I know if a socket is shorted. Can I do it with resistance ? I can't keep a fuse in it, it blows. I guess I can do that without engaging the light switch.
Can you elaborate on that test. There's only 6 sockets. 2 parking lights in front, and 4 bulbs in rear lights.

I've heard the dash lights might be part of the circuit, but it has a separate fuse. But they are connected to the switch.

I do have a suspect socket in the rear, but the blinker and brake lights work on that socket. Might be obvious to some how that can happen but not to me.