Symptom: Failed tailgate light cluster on the drivers side that contains the rear light, reverse and fog lights.  Removing the cluster and testing it independently showed the cluster is working fine so the issue is with the electrical feed to it.

Cause: Wires have become work-hardened and snapped in the flexible gaiter between the body and the tailgate. See attached image

Others have also fixed this issue but I thought I would post here with some info on the connectors I used as there is not much room in the rubber gaiter that covers the loom between the tailgate and the body and there is also very little slack in the wires.

To remove the gaiter you need to pull the rubber foot from the snap-in plastic connector by getting your fingers between the rubber and the car body and pulling the gaiter out and back.  To put it back on again you need to get the plastic oval out of the car by prising back each of the clips one by one with a small screwdriver

There is practically no slack in the wires to work with to make a repair and very little spare room in the gaiter.  You have three options to fix it in order of cost and effort:

1. The "proper" solution - replace the whole loom
2. Replace this section of the loom with a section from a different area of an old loom (so that the wires are not work-hardened)
3. Repair the wires in-situ

I did option 3 which is the quickest and cheapest but will probably not last so long.

To do this I used low temperature solder seal connectors like these: https://www.amazon.co.uk/Kuject-Connectors-Waterproof-Insulated-Automotive/dp/B07BJX51VT

These have a very thin profile when set and don't require you to try and get crimping tools in amongst the other wires on the loom, which will probably cause more damage.

You need a mini heat gun with a reflector shield as well: https://www.amazon.co.uk/Traderight-Temperature-Handheld-Electronics-Embossing/dp/B0FYD9T8XD

I'm actually amazed that it's taken 13+ years for this to fail on me as the bend radius on the wires is a lot, so the amount of flex they go through when opening the boot is more than 90 degrees each time.  Not a great design and should have more slack in it really.  I will probably need to do this properly in a year or so but this will get it through the MoT!

 

I should add that continuity testing at the light was inconclusive;  there was continuity between the wires and the earth because the broken cables had splayed outwards and were touching each other and a negative cable where the plastic sheathing had cracked away