Tail light brake light issue

[AuroraGirl]

All,

I am having passenger side tail light issues 84 K20.
Can I bypass 4 prong tail light harness? What purpose does it serve besides for a trailer?

When I have lights on, right rear turn signal wont blink it just stays solid.
When I have lights on, and I press the break, rear break light turns off on passenger side.
When lights are off I press I press the break and break lights turn on but is super dim on passenger side.
When lights are off and I press right turn signal, it blinks but Is super dim on passenger side.

I checked the ground located behind the driver side tail light socket and cleaned that. Then I replaced the passenger side tail light socket for the blinker and break light to no change. SOS.


My next thought is it does have the 4 pronged harness located under the tailgate that someone did a horrible splice job with wires that are exposed. I would like to just by pass it entirely because where I am at in the world I need it to work now and wont have a trailer for a few years.

Are you saying your tail light harness has the 4 flat connector in between the truck harness and tail light harness and you want to remove it, or that someone put taps/spliced into the wires running across that feed the other side? The harness should come down the driver side and then cross over below the tail gate to the passenger. The harness, iirc, has a plug up on the frame a few feet, maybe a foot, up toward the front on the driver side, that is where a T plug usually is placed to get trailer functions.

 

[brooksman9]

I dont remember my exact issue but I ran a ground from the grounds at the driver side tail light to the frame and it cleared it all up. Bad body ground???

 

[AuroraGirl]

I dont remember my exact issue but I ran a ground from the grounds at the driver side tail light to the frame and it cleared it all up. Bad body ground???

I believe the only stock body ground is the fender to the battery, which of course any corrosion from the bed connection to the frame, is right there gonna show up a lot lol! SO wise. the cab to the engine to the frame/battery is another, but thats depending on great engine grounds!

 

[84Squarebodlvr]

Are you saying your tail light harness has the 4 flat connector in between the truck harness and tail light harness and you want to remove it, or that someone put taps/spliced into the wires running across that feed the other side? The harness should come down the driver side and then cross over below the tail gate to the passenger. The harness, iirc, has a plug up on the frame a few feet, maybe a foot, up toward the front on the driver side, that is where a T plug usually is placed to get trailer functions.

Unless I am mistaken This is the 4 prong plug located beneath the tailgate that I believe is for a trailer. (Looks crazy I know lol). Its male side has wires going to the trailer plug socket, then to the passenger side rear head light that is having issues.

My solution I think is to just remove it entirely and use butt connectors to just give good power and ground to passenger side tail light.

 

[84Squarebodlvr]

I dont remember my exact issue but I ran a ground from the grounds at the driver side tail light to the frame and it cleared it all up. Bad body ground???

Interesting that’s a good idea. I’ll give it a shot! Thanks y’all

 

[Grit dog]

Unless I am mistaken This is the 4 prong plug located beneath the tailgate that I believe is for a trailer. (Looks crazy I know lol). Its male side has wires going to the trailer plug socket, then to the passenger side rear head light that is having issues.

My solution I think is to just remove it entirely and use butt connectors to just give good power and ground to passenger side tail light.

Terminology when discussing these things helps. “Passenger side rear headlight” ???
That said, yup, someone ****** rigged the trailer wires in with scotch locks.
You can spend a lot of time ******* around with old wire and plugs and sockets, and get it to work probably until a dog ****** on the rear tire and it all shorts out, or removing the offending **** and redo the old/hacked up/shorted out wiring.

 

[AuroraGirl]

My squares tail light harness actually was similarly hacked.

If you want to fix it i would recommend pulling the harness off the truck (just plastic retainers that either open or pop out, undo the sockets from the tail lights, unscrew the ground from the bed on the driver side, and then unplug the harness from the trucks harness. , undo the license plate lights , pop all your bulbs out, then you should be able to pull the harness away. At that point you can bring it to your bench and repair it. all those taps have to come out, and youre gonna need to use heat shrink and something like solder-splices or just solder if you are able to do that. Cleaning the wires to see the original colors accurately does help.

But you can also buy the tail light harness new, and a later square has superior tail light sockets than the earlier ones like my truck. but you can use, to my understanding, any fleet side tail light harness if you want to shop used.

I would not recommend butt splices because they would all be in the same spot , near a plug, and thats going to bulk the harness, create a lot of weight, make guarding it for the future more difficult, and increase complexity for you to fix it.

But you can do it, I guess, just not advising it.

 

[Grit dog]

What AG said. And the solution to a pile of butt splice connectors in the same spot is stagger them and/or invest in a shrink/solder splice kit.
I may retract my statement in 5 or 20 years but IMO they are a slick, slim, clean, weathertight, solid solution to splicing automotive wires.
I love em. Except in real tight areas where heat is not able to be applied. Anything from a bic lighter to a heat gun works. Although lighters are messy with the soot.

 

[AuroraGirl]

What AG said. And the solution to a pile of butt splice connectors in the same spot is stagger them and/or invest in a shrink/solder splice kit.
I may retract my statement in 5 or 20 years but IMO they are a slick, slim, clean, weathertight, solid solution to splicing automotive wires.
I love em. Except in real tight areas where heat is not able to be applied. Anything from a bic lighter to a heat gun works. Although lighters are messy with the soot.

And, in more sensitive situations, carbon leftover is conductive which would not be wanted, but here i doubt it would hurt anything even with LED bulbs

 

[Grit dog]

And, in more sensitive situations, carbon leftover is conductive which would not be wanted, but here i doubt it would hurt anything even with LED bulbs

??

 

[AuroraGirl]

??

if you used a bic lighter or a torch, the fuel would leave soot potentially either a lot if youre bad at it or just small amounts which are unavoidable, but it wouldnt matter in the tail light circuit, so it would be fine.

Carbon from those sources is conductive. but the amount left over and the lack of it being sensitive/fine electronics makes it something that wont be a big deal

 

[Grit dog]

if you used a bic lighter or a torch, the fuel would leave soot potentially either a lot if youre bad at it or just small amounts which are unavoidable, but it wouldnt matter in the tail light circuit, so it would be fine.

Carbon from those sources is conductive. but the amount left over and the lack of it being sensitive/fine electronics makes it something that wont be a big deal

Ahhh ok. And it’s on the outside of the insulation so even more of a non issue. And it wipes off.

 

[AuroraGirl]

Ahhh ok. And it’s on the outside of the insulation so even more of a non issue. And it wipes off.

not quite.. but im not about argue with you about this.