69 valiant electrical gremlin turn signal and license plate light

Turn signal- I see two wires going to it. Are there two connecters on the bulb/ two filaments in the bulb? This means that your turn signal housing does two things- it is a park light and a turn signal (two things). This in turn means there is no third wire- a ground. These ground through the metal housing. Since most park lights are mounted in plastic grills (which insulates it) there must be some provision to ground the housing. Look closely at the wire loom.There must be a third wire to ground the housing. Both sides need to be grounded.