72 Charger Tail Lamps not Lighting

[JR_Charger]

A little backstory, I've been restoring the car and everything has been off the back of the car and repainted. The bumper was originally chrome, but I've painted it. The tail lights worked before I took everything apart. They don't work now.

Here are the wiring diagrams from the FSM -

I'm not an electrician and I don't understand this. If I were guessing, I'd say L7-18BK, D7-18BR, D8-18DGN and B2A18V should be providing power. The back up lights have one line going in because they only have one filament, and the regular tail lights have two lines going in because they have a 2nd filament for the brakes. The left side marker lamp has a line coming out that goes to ground, because it can't ground on the plastic lens housing. The right side marker lamp has a line coming out that goes to ground on the outermost passenger side tail lamp.

I think this symbol -

indicates that the socket is grounding on the bumper.

So far the advice I've gotten is that the tail lights aren't grounding. I painted the bumper, the bumper support brackets, and the back of the car - so I wonder if there is too much paint for the lights to ground through? If that's the problem is there a way to run a new ground?

FWIW I tested the connector in the trunk and could only get two of the prongs to light up my testing light, so my idea that all four provide power may be incorrect. I'm beyond my depth here.

 

[72RoadrunnerGTX]

‘72? Aren’t the tail lamp housings on Chargers made of plastic as they are on the Plymouth side that year? If so, the grounding is included in the lamp harness and body grounded on the left side of the trunk.

 

[JR_Charger]

I do have the ground on the driver's side of the trunk, but I believe it's only for the driver's side marker lamp. Pretty sure the Charger's lamp housings are metal. It was hard to install them without scratching up my bumper paint. There are a couple different housings though. It's possible the R/T and/or Rallye housings are plastic. I doubt it, but I've never seen them.

 

[Rockland71GTX]

You do have 4 circuits that provide power at that plug. The 'L' circuit is the parking lights. The 'B' circuit is the backup lights. The circuits 'D7' and 'D8' are the left and right directional/brake lights. The parking and reverse lights don't go through the turn signal switch, only the directional/brake lights.
The easiest thing to do would be to pop the lenses off and check the ground at each socket individually. It only takes one to screw things up!
Even if the housing itself has ground, corrosion can cause a poor ground at the socket. You can solder a wire to each socket and run it to a good ground and be done with it.

 

[Texas charger 73]

‘72? Aren’t the tail lamp housings on Chargers made of plastic as they are on the Plymouth side that year? If so, the grounding is included in the lamp harness and body grounded on the left side of the trunk.

View attachment 1548154

73 started plastic on chargers... 71-72 on chargers was pot metal that grounded through the body/bumper/housings

 

[JR_Charger]

73 started plastic on chargers... 71-72 on chargers was pot metal that grounded through the body/bumper/housings

. . . and there it is. There were painted bumper Chargers though, so how did the tail lights ground on those? I think they were coated in some kind of rubber too (haven't seen one, but I've been told about it). So if I'm having grounding issues with a little paint and primer, Chrysler must have done something different for the rubberized, painted bumpers.

 

[Texas charger 73]

. . . and there it is. There were painted bumper Chargers though, so how did the tail lights ground on those? I think they were coated in some kind of rubber too (haven't seen one, but I've been told about it). So if I'm having grounding issues with a little paint and primer, Chrysler must have done something different for the rubberized, painted bumpers.

i found the grounding problem when i put 72 taillights in my 73.. how I fixed mine was I soldered a ground wire to each terminal and then grounded that to frame.. since that fix no issues..

 

[Texas charger 73]

i bet the ones that came with the painted bumpers had a separate ground added from the factory

 

[JR_Charger]

The rubber bumpers in 71 were only available with standard tail lights which had plastic housings and the ground wire in the trunk.

 

[JR_Charger]

Most likely I'll run my own ground wires as suggested, but I am curious if there are any other options availabe, such as 73/4 wiring harnesses or LED conversion?

 

[T2R9]

OK, that is what I remember. Only R/T tail lights with colored bumpers.

 

[Nacho-RT74]

73 started plastic on chargers... 71-72 on chargers was pot metal that grounded through the body/bumper/housings

71 standard are plastic

 

[JR_Charger]

So they switched to metal for one year? It must not have worked well.

 

[Nacho-RT74]

71 R/T were pot metal, like all 72s… then all 73/74 are plastic, like 71 standard.

I can be wrong thought on the 71 standard? From the distance they have allways look like a plastic assembly to me

Tail Lamp Assy# 3478748 / 3478749 - Pair - Dodge Charger - 1971 - ORIGINAL/RESTORED - SHIPS FREE TO LOWER 48 - Blue Star Performance

I can see the ground wire on passenger side grommet, diff from 73/74 which is on driver side

 

[T2R9]

71 Standard is plastic. I have a couple sets here.

 

[JR_Charger]

What size wire should I use for the grounds?

 

[Nacho-RT74]

stock plastic housings with ground wire used same than the positive lines… 16 gauge

 

[72RoadrunnerGTX]

Stock would be 18ga, see diagrams above.

 

[JR_Charger]

Stock would be 18ga, see diagrams above.

The little side marker lamps use 18 gauge, if I'm reading the diagram correctly. Nacho-RT74 could be right about 16 gauge on the main lights.

Where on the frame should I put the ground at?

 

[72RoadrunnerGTX]

Looks like there are couple of segments at 16ga, ring terminal to splice, splice to right side bullet connector. Most of it is 18ga. Shouldn’t matter, won't hurt to go up a size if in doubt.