I have been having difficulty with the lights on the back of my 71 custom.I have some of them working......others are not, like the brake lights...It seems to be a big mess.....one signal light working the other is not. I have checked the grounds, replaced the stop light switch, replaced all of the flashers, etc....My question is what is the metal connector that was to the center of the truck...my guess is the tag light...but, I cannot remember it being there when I put the roll pan on the old truck...It is kinda rusty looking....like it hasn't been hooked up for a long time....Helpl here...Nomadic.

 

The license plate lights should be have been hooked to the brown wire originally. That was your running light wire to the back of the truck.

You replaced your flashers...but how about your turn signal switch(on column)?? This is the main control for your rear lights. It decides if both flash or just one side/the other. If it has a bad connection, you will lose rear lights. If the column has been changed, the switches are YEAR SPECIFIC!!! Not sure if each year, but certain years will not work properly with others(mainly you will lose certain rear lights).


You only have FOUR wires going to the rear of truck Yellow, green(right-left turnsignal), brown(running), and back up lights(?dont remember what color?). You need to check the wires under the truck to see if you are getting anything at the plugs. If nothing there, then you have issues up front(like possible turn signal switch). If you get power at the connections, then you have issues with the light sockets.

Larry