[Potatrix]

Hello Folks!

I'm trying to install these GTI tails I just got, the Driver's Side works fine, but the Passenger's Side acts all funky.

It looks like the Previous Owner might have messed with the wiring.

With your help, maybe I can figure out what the PO did to it, and how to make it OEM again.


Here are the details

Picture 1

These are the aftermarket tails that were on my car when I bought it.

I've seen multiple like this online, all on Ebay from different manufacturers, but I haven't been able to find any documentation on them to find out how they might have been installed.


BKA Motor has a set, somewhere in the description it says they are "Euro Style Tail Lights" Not sure if this gives me any important information.

LokTong also sells a set of these, little to no description of them, states: Professional Installation Is Highly Recommended. Well that doesn't sound good.

Now for the wires.

Picture 2

This is a picture of the 5-pin plug that connects to the Drivers Side Tail Light.

As you can see, the Black/Red wire has been taken out, this is the way it was when I got it, and I'll show you where they put it before I freed it.

The metal contraption on the end is something I put together from an old wiring harness to try to put it back into the plug. It's very half-assed.



Let's Continue

Picture 3

This is a picture of the the Aftermarket wires in the Driver's Side Tail Light.

I'd like to point out this blue wire in particular.

When I first opened this up to start removing things I noticed that the black/red wire, from Picture 2, was joined with this wire.

I can verify that this blue wire links directly into the Driver's Side Brake Light.

I have no clue why it was set up in this way, but a good clue is: When I separate the two wires, the Passenger's Side Brake Light stays on when the lights are turned on.

"Well where is the red/black wire SUPPOSED to go??" That's a good question.

Picture 4

It looks like the red/black wire was supposed to hook into a red wire. Makes sense.

Picture 5


This picture is a little fuzzy I apologize. I followed the red wire from Picture 4 to the LED's (for orientation, those are on the top of the tail lights). Which means they are not properly grounded?

This might explain why only the top 2/3 rows of LEDs work on my lights.



Let's take a look at the other side

Picture 6


These are the wires to the Passenger's Side Aftermarket Tail Light.

Here you can see that another red/black wire merges yet again into the blue wire which leads to the Passenger's Side Brake Light, and also that I haven't messed with it yet.

This red/black wire is paired with a brown wire that appears to go up the hatch, I have no idea where it is supposed to go, but it likely grounds the Passenger Side Brake Light

Keep this wire in mind.

Now the OEM wires on the Passenger's Side

Picture 7

Here's the 8-pin plug for the Passenger's Side Tail Light.

I notice that, though it is an 8-pin plug, pins 4 and 5 are missing. The plug and wires also don't appear to have been tampered with.. Is this normal?

This 8-pin plug is also the other end of the 5-pin plug on the Driver's Side Tail Light from Picture 2.

One Last Thing

Picture 8

This is the OEM Passenger Side Tail Light Circuit Board.

I'm showing you this only because I'm a little concerned about the 8-pin female plug. There appears to be some rust/corrosion.

The 2 pins that are rusty are the pins that the red/black and brown wires connect to in the 8-pin plug from Picture 7.

I'm pretty sure both of these wires must be ground wires, maybe these rusty connectors are a part of the problem?


SYMPTOMS

I'm sure many of you have had similar issues with grounding, as I've read about a lot of them.

The Passenger Side Tail Light will have a different reaction based on many things. To name a few:

1. How far the 8-pin plug is pressed in
2. Which lights I turn on
3. How far I jam the red/black wire from Picture 2 into it's place in the 5-pin plug.

The results are less crazy with the red/black wire from Picture 2 plugged in, but the Passenger Side Brake Light tends to stay on.

I can gather more detailed information about the symptoms if you feel it is relevant, though I think it's not.


QUESTIONS:

Of course I'd like some suggestions as to how to get my setup back to OEM. I've taken a look at some Bentley Manual pages but it hasn't answered all of my questions.

Here are some questions I have:

1. How should I get my red/black wire from Picture 2 back into place? Should I just get a completely different wire from another car?

2. The 8-pin plug from Picture 7. Is it supposed to only have 6 wires?

3. What would you recommend for cleaning the 8-pin female plug in Picture 8? Does it look dirty enough to cause a problem?

4. Where the heck is the red/black and brown wire from Picture 6 supposed to plug into? I don't see a place on the OEM tails for the red/black, yet it was spliced into the blue for the Aftermarket tail?


Thanks for reading! I've tried to detail every part of my problem as best as I can, but if you need more information please let me know!

I'm really sick of this problem and I'd like to get it fixed!~

 

[Potatrix]

Just an update,

I had another guy look at the problem

I showed him the mystery black/red and brown wire and he though it was probably supposed to go into a 2-pin plug that hooks into the Passenger's Side Tail Light.

However, upon further inspection, it looks like this brown wire actually connects to a screw which pushes it up against the body of the car (a ground), so it can't go into a 2-pin plug if it's not supposed to hook into the Tail Light..

Then I noticed something else:

There's a spot for a 1-pin plug.. Could it be that this red/black wire was supposed to hook into this plug?

So I have a request

Can anyone take a picture of their OEM Tail Light setup in their MK3 Golfs? Particularly the Passenger's Side.

It's weird, but I can't seem to find something as simple as this online, but I think it's all I need to figure out once and for all what's going on here.

Much thanks!

 

[oxygen454]

Did you ever get your wiring figured out? If not I could take some pics of my wiring. Should be similar.

 

[luism_12x]

I think you should try to clean up the light bulb tray with a electrical connector cleaner to see if it helps. I know I got some aftermarket tail lights and they too acted funny. Turned out that my light bulb tray was exposed to water and it shorted. I tried to clean it and it helped a little until I replaced it. Then everything worked smoothly.