Roscoe52

We all share the problem of the third or trunk-mounted brake light failing due to the wiring breaking inside the rubber boot. The well-known problem is the 2 pinch points - the red arrows in the pictures that follow (2nd and 3rd images borrowed from a Youtube video). Everything looks great when the trunk is open but as it closes things go from bad to worse for the wires:


My solution (after previously just replacing the wires and having them break again a couple years later and then after a lot of trying various things to see how they worked as the trunk lid closed) has been to trim the rubber boot down to just the 2 ends, then I drilled a hole into the side of the resulting tube that goes up into the trunk lid and fitted the wire into the trunk lid that way (green arrow in the first pic below) so that the wire is now exiting the tube towards the left side of the trunk so that the bending of the wire as the trunk lid closes is now more of a rotational movement that is spread across the whole length of exposed wire as seen in the next 2 pics:

I used 22awg sheathed wire, the same gauge as the existing brake light wire - the LED's draw very little current. While I was at it I left a foot or so of extra length coiled at each end just in case. All joints are soldered with staggered joints and individually heat shrinked and then heat shrinked again over the top of both joins. (Take care if you plan on using an open flame for the heat source here, you are working near the gas tank! I used a heat gun and made sure I had plenty of ventilation.) I chose to remove the trunk lid trim to do this job - it is just held in place with push pins that just pop out, and I figured that it would be easier to work with it out of the way. There are posts in various places online with details of exactly how to remove it so I will not repeat them here.

I hope that this helps the next R129 owner who loses his (or her) third brake light! It's about a 3-beer job, maybe 4 if you want to drag it out.