Board logo

Wiring fix with no slack on the wire
Slimy38 - 11/3/26 at 07:57 AM

This is a tintop issue but I'm hoping you clever people have a solution. My Superb estate is having some tailgate issues. It started with the number plate lights, now it's progressed to the open button not working every time. I'm 99% sure it's in the rubber flex between tailgate and chassis, because I can wiggle it and get the lights coming back on. I'm 99% sure I can remove panels and take the wiring out, but I'm not going to be able to find a replacement part so it looks like I need to repair it.

The problem is that because the break is likely inside the rubber flex, I'm not going to have any slack on the wires to be able to bring them together to repair them. So given their location, the lack of spare wire, the required movement etc, what's the best way to join the wires?


cliftyhanger - 11/3/26 at 08:16 AM

You don't want a join anywhere near where it flexes. So 2 joins, one either either side makes sense. Not sure if Tri-rated cable would be best, or pinch a section from the wiring where it doesn't flex and add a 3rd joint.


Slimy38 - 11/3/26 at 08:25 AM

quote:
Originally posted by cliftyhanger
You don't want a join anywhere near where it flexes. So 2 joins, one either either side makes sense. Not sure if Tri-rated cable would be best, or pinch a section from the wiring where it doesn't flex and add a 3rd joint.


I've got a load of wiring left over from my kit car build so hopefully I'll be able to find something rated correctly. Two joins makes sense though. I don't know what tri-rated cable is so I'll look into it, is there an 'extra flexible' wire available that would be better?

What's the best thing to use for joins here? Crimps?


nick205 - 11/3/26 at 10:06 AM

cliftyhanger - is correct here, avoid making a joint in the hose part where the cables flex and move. THAT'S where they where out!

Had this same issue in our VW Touran passenger door a few years ago. Knackered wire in the hose!
Managed to remove the door card and trim by your foot inside the car. Joint either side and a clear run of NEW cable through the hose.
Problem resolved.

Even if it takes you a bit more time and effort it's worth it to avoid having to go back and do it again.


Slimy38 - 11/3/26 at 10:15 AM

quote:
Originally posted by nick205
cliftyhanger - is correct here, avoid making a joint in the hose part where the cables flex and move. THAT'S where they where out!

Had this same issue in our VW Touran passenger door a few years ago. Knackered wire in the hose!
Managed to remove the door card and trim by your foot inside the car. Joint either side and a clear run of NEW cable through the hose.
Problem resolved.

Even if it takes you a bit more time and effort it's worth it to avoid having to go back and do it again.


Aye, I really don't want to do this more than once. And I think the emphasis on NEW cable is also right on the money. I'll have to open it up and have a look at the wire gauge, while some may be signal wires I suspect if the lock motor wire is also broken that could be a bit thicker.

Given how many cars I've had with electrical gubbins in doors and boot lids I'm amazed and a little disappointed that the youngest car I've owned is the one that has failed.


nick205 - 11/3/26 at 01:58 PM

quote:
Originally posted by Slimy38
quote:
Originally posted by nick205
cliftyhanger - is correct here, avoid making a joint in the hose part where the cables flex and move. THAT'S where they where out!

Had this same issue in our VW Touran passenger door a few years ago. Knackered wire in the hose!
Managed to remove the door card and trim by your foot inside the car. Joint either side and a clear run of NEW cable through the hose.
Problem resolved.

Even if it takes you a bit more time and effort it's worth it to avoid having to go back and do it again.


Aye, I really don't want to do this more than once. And I think the emphasis on NEW cable is also right on the money. I'll have to open it up and have a look at the wire gauge, while some may be signal wires I suspect if the lock motor wire is also broken that could be a bit thicker.

Given how many cars I've had with electrical gubbins in doors and boot lids I'm amazed and a little disappointed that the youngest car I've owned is the one that has failed.



With you all the way.

On my 57 plate VW Touran, even the boot catch was motorised. It failed (had to tie the boot shut with a very long USB cable to get home), I replaced the catch, problem solved!
Gone are the days when it was a wire pulling the catch.


cliftyhanger - 11/3/26 at 06:47 PM

Tri rated stuff is meant for control panels etc, and has good flexibility. Better than std cable in my book.
Yoiu can get "extra flecxible" cable, used for testers and so on. That may be even better.
EDIT
No solder anywhere near where the cable flexes, it WILL break. I would solder and heat shrink but at least 100mm from where it moves.

[Edited on 11/3/26 by cliftyhanger]


adithorp - 11/3/26 at 10:43 PM

Common issue on all models but VAG brands expecially.

If you're going to repair it, then you need to add new section with joins either side of the flex. Even if some wires aren't broken it's best to splice new sections into those as well; s they'll probably fail soon anyway. To do it, it's best to pull the whole sub-loom out first. It's tricky to make a new job of it otherwise. Stagger the joints so you don't end up with fat sections with all the joins together. Beware though, VAG looms often use all the same colour (white?) wires. If the wires are completely broken matching the right ends to each other can be a batch.

Much easier however is to get a new sub-loom. You can find them on ebay.


Slimy38 - 12/3/26 at 08:54 AM

Thanks Cliftyhanger and Adithorp, that's useful information. I did see the sub looms on Ebay and have a few bookmarked, although as with other things VAG there are plenty of variations. I'll get the panels removed and see if there are part number tags.