I have the back bumper off the car of the 71 charger (car being painted) I took the tail light ass. Out of the bumper to paint it. Is there any way I can bench test each set of tail light BEFORE I put it back into the bumper???

put a ground wire on the body of the tail light, probably through the bolt hole that holds it to the bumper.
then apply positive to the pigtail coming out of the lamp socket.
if it lights up, then it works.

if not you have to clean up where it will be grounded.

Sweet thank you

I gave it a try.....nothen. the light sockets have some junk sealer around them that someone put on (keep water out) im sure the sockets wasnt grounded.... the sockets also had 2 wires each... wouldnt one of them be ground or??

How many filaments in the bulb?

2 filaments = 2 wires with the housing being ground.

Hmmm I didnt look at that. Not sure if there is two brake/turn signals and a back up or one of each

doesn't matter.
each wire goes to a different filimant but the housing is still the ground.

They also make a replacement housing with a ground connection built into it. you have to run a seperate wire to ground the socket.

I did that because of the same thing you have. last guy went crazy with some sealant and almost nothing would ground in the back.

generic help section and you will see a tab on the socket you can wire a ground wire to with a standard spade connector.

Il have to check into that