72 Charger tail light bulb question

[hpg4815]

1972 Charger, I have the old tail light harness that screw the bulb sockets into the lamp housing. The harness is a mess so I am rebuilding it. I already bought the harness that gets me to the truck from the dash harness.

So to make sure things are working I am trying to test the bulb assembly individually to ensure they work first. For example I wired up the two reverse light sockets and tie into the plug in the truck coming from the dash. I can see power to one of the prongs in that plug when I put the car in reverse. Then I wire up my sockets. The socket gets power. I put new bulbs in the sockets and but they are not coming on. Rear side Parking lamp comes on ( just noting something is working)

My bumper assembly is not on the car. I am wondering… do i need to put the entire bumper assembly in the car first and then try to put harness together? I wonder if the socket are being grounded by the bumper. Or that maybe the entire assembly needs to be put together first. The harness from the dash to the trunk has a ground that I installed just FYI.

Let me know your thoughts or if you need additional info. I can provide pics too.

 

[WileERobby]

I'm not in the mood for thinking right now, so all I'll ask is if you have it grounded.

 

[hpg4815]

I'm not in the mood for thinking right now, so all I'll ask is if you have it grounded.

Have what grounded? The harness to the trunk from the dash has a ground. Is there another ground needed?

 

[WileERobby]

The body is the ground. Wires supply power. Taillamps must be grounded. Sockets must be grounded.

 

[Manfred]

Owners manual says only use brass based bulbs. I had a weird turn signal issue awhile back and I replaced 4 aluminum based bulbs. problems solved, I'm guessing ground issue. Might be worth a swap to rule out a possible problem

 

[hpg4815]

The body is the ground. Wires supply power. Taillamps must be grounded. Sockets must be grounded.

So my statement that the bumper assembly needing to be installed is how to get the sockets grounded?

 

[WileERobby]

So my statement that the bumper assembly needing to be installed is how to get the sockets grounded?

The body is the ground.

 

[70chall440]

The harness needs to be grounded. You can test each circuit (reverse lights, running lights, turn/stop lights) individually but you have to ground the sockets.

 

[Nacho-RT74]

Plastic housings are wire grounded, but pot metal housings are body grounded. This is the case of all the 72 housings and 71 R/T, which doesn’t get a ground wire for tail lamps housings. Can be added thought

 

[hpg4815]

Just to finalize this post... I bolted my bumper assembly to the car and all the lights started working. Issue was I can not figure out a way to ground the sockets to the car while the bumper and its brackets where not bolted to the car. essentially the objective was to validate all the lights work before attaching the bumper assembly to the car. Thanks all for the responses.