Tail light electrical issue - help needed

[dbo_texas]

I'm having an issue with one tail light where it only seems to work properly when the metal body of the light is touching the metal body of the other light or any chassis ground. I'm assuming this is a grounding issue, but when I probe all the ground pins/wires on each side (tail light housing, and chassis harness) they all seem to be fine. For example, the black wires coming from the chassis harness into my Weatherpack connector all have good ground (low resistance). I re-pinned the male & female ends of the Weatherpack connectors just to be sure it wasn't something I did when crimping the ground wires together but still get the same behavior.

The other 3 tail lights work as expected (see video below). My working assumption is that something is messed up with this one tail light housing so I've ordered a new one from FFR. In the even the new tail light doesn't resolve the issue, any electrical gurus here have any ideas for me to investigate? All other electrical seems to be working perfectly. I'm using the Breeze exterior lighting LED kit. Flashers/turn signals work fine. Brake light & running lights work on PS, but on DS they only work when the metal body is touching ground (it works touching the metal on the other tail light housing OR any chassis ground such as a CLECO going into the frame).

Video demonstrating the issue:

https://youtube.com/shorts/fonsuZBdavA?feature=share

[seagull81]

Darryl I assume you have swapped the housing with on of the other working ones to be sure the fault moves with it. Other than that I'm at a loss for answers.I think you are correct that the housing is the issue. You might try posting this on the Austin FB page. Maybe one of the locals can help you out.

[dbo_texas]

Darryl I assume you have swapped the housing with on of the other working ones to be sure the fault moves with it. Other than that I'm at a loss for answers.I think you are correct that the housing is the issue. You might try posting this on the Austin FB page. Maybe one of the locals can help you out.

Yeah forgot to mention when I swap the tail lights, the problem follows the light so that's more evidence the issue is with that specific housing. New FFR part hasn't shipped yet but I'm hopeful it will resolve the problem. If not, I'll be back on here chirping for help :)

[michael everson]

the ground wire is crimped or soldered to the housing. I would try replacing the wire or run a separate ground from the chassis to the bolt holing the light in.
Mike

[dbo_texas]

the ground wire is crimped or soldered to the housing. I would try replacing the wire or run a separate ground from the chassis to the bolt holing the light in.
Mike

Thanks Mike - yeah I did try re-connecting the black wire directly to the tail light housing metal body but that didn't work. The black wire is attached with a type of ring lug that is somehow bonded to the metal body. I was thinking maybe that ring lug somehow had corrosion on it and was preventing a good ground, so I clipped the wire and soldered it directly to the housing. But it didn't work. I'm wondering if there is a break in the actual wire somewhere....that would explain it for sure. I will try attaching a separate ground wire from chassis ground to the housing tonight and see if that works...if so, it confirms a bad wire and the fix is simple (replace black wire with new one). I'll report back after I try it.

[dbo_texas]

Well we can close the book on this one. I did a continuity test from the connector to the metal body of the tail light and got no connectivity. So this told me definitively there was something wrong with the ground connection, either at the wire or where it terminates to the body. So I de-pinned the Weatherpack connector and started tugging on the wire, and lo and behold....there wire pulled right out of the factory installed heat-shrink sleeve. After pulling out the other end, it's very clear somebody has tinkered with this tail light. The wire was broken inside the sleeve and there's solder on both ends so somebody at some point joined this two pieces and did a crap-tastic job of it. One of the screws is also stripped out that holds the lens on. At this point no telling how this happened (at tail light factory, or from the previous builder). I installed a new ground wire and voila...everything works.

https://thefactoryfiveforum.com/attachment.php?attachmentid=214154&d=1747865961

[seagull81]

I'm glad it was something simple. Now "Git 'ER Done"!