69 valiant electrical gremlin turn signal and license plate light

sketch said
you saw the pictures of the passenger one right? that is the third ground wire i think? on the passenger side, it doesn't need to be plugged in for it to work fine whereas the driver side light HAS to have the ground plugged to it for the light to function in any capacity.

sketch said
That is the issue. I can see where the slots are and I push it in gently but can’t get the 1/4 turn. Crazy thing is the bulb can go in backwards but then blinker doesn’t work. I thought maybe there is a trick or something as the bulb should only go in one way.

I suppose there could be something wrong with the socket. They are quite simple and were quite dependable when new. In the bottom of the socket is a small board with 2 little contact. Those contacts are on the ends of the 2 wires. A spring beneath the board allows it to move up and down in the socket so the wires move a bit too. Rust down in the socket along with stiff wires can interfere with board movement.
The 2 little tangs on the bulb are 180 degrees apart so the bulb can start in 180 degrees wrong. If the board doesn't move down far enough the bulb tangs wouldn't go deep enough to reach the groove/route where they turn. If the bulb is 180 degrees wrong it wont go deep enough to turn regardless.
You could have a broken board, or spring, who knows?
Rebuild kits for these sockets are available at Amazon, etc... 68130 by GROTE - Replacement Lamp Socket Repair Assembly - Double Contact, 7 1/2" Long
You'll have to get the wiring correct to bulb orientation. The park lamp wire is the same color wire for both left and right fixtures. So temporary hook up that 1 wire to new socket wiring and pull the park lamps on. If this bulb is a much brighter that the other, you have park circuit tied to turn element of bulb. Move the temporary connection to other wire and confirm both park lamps the same brightness. Complete both wire connections, done.