Fellas, 1975 FJ40 for clarification. Thought the the license plate lights were not working, volt meter showed 10-12 volts but stil could not get a bulb to work. Ordered two new bulb sockets. After installing the first, still no illumination…… unlatched and moved swing the door open and BAM!!! Both new and old bulbs and sockets worked…. Now assuming it would be a grounding issue, this is where I’m running into dead ends. Being that the lights them selves ground out to the license plate racket, I have removed cleaned and refastened the bolts to the license plate bracket, replaced the doors hinges with stainless harderware and still running into flickering and inconsistent illumination. Any help would be appreciated in which way to go. Have great week!