A6 Avant C5 toplight intermittent/wiring question

**JaypeeA6** · 13-01-2019,11:26 AM

Hi folks, the middle brake light works on and off which I'm not too concerned about but the ridiculously intrusive beep that goes off every few times I brake is driving me mad!

Consensus online seems to be that you can't do anything about the noise and of course I'd rather the toplight worked without fail.

As it's intermittent I'm assuming a wiring fault. The flexi hose from the roof to the top of the tailgate seems the best place to start. Do i just prize that off? Never done that before and I don't want to make anything worse!

Any other thoughts or suggestions gratefully received.

**Stavros_Davros** · 30-01-2019,12:03 PM

Originally Posted by JaypeeA6

Hi folks, the middle brake light works on and off which I'm not too concerned about but the ridiculously intrusive beep that goes off every few times I brake is driving me mad!

Consensus online seems to be that you can't do anything about the noise and of course I'd rather the toplight worked without fail.

As it's intermittent I'm assuming a wiring fault. The flexi hose from the roof to the top of the tailgate seems the best place to start. Do i just prize that off? Never done that before and I don't want to make anything worse!

Any other thoughts or suggestions gratefully received.

Hi Jaypee,

Sorry for the late reply, I've had forum issues and couldn't see the post you made that I can advise on.

I've had the same issue with my high level brake light since buying the car, sometimes the intermittent light and dash alarm was worse than others, it got worse in the colder damp weather.

My light was changed with a new unit from Germany at great cost originally by the previous owner a few months before I bought the car but that was faulty too and still causing problems so I assumed that it was the wiring and I spliced a new connector onto the loom end to no avail. The problem is rarely down to bad wiring, it's pretty much well protected, I noticed no wear or damage at the flexi so before you start time consuming tearing apart, attach a 12v light or buzzer to the wiring plug on the harness and get someone to press the brakes, if it works consistently well your wiring is good, I wired a small buzzer up and took it for a drive, it always worked when I pressed the brakes.

These light units are notoriously crap, they develop dry joints in the long circuit board and have many connections which you cannot get to, if a PCB component fails the whole light fails, the main power terminals at the end are a good place to start, re-solder the points where they enter the board, you may have to melt out a section of the grey back plate to get at them, if that doesn't work then you have a few options.

1/ Replace the lamp with a known working unit/new unit - or like I did...

2/ Repair the light using a piece of adhesive backed LED strip lighting from eBay for about £3

You need to break the tabs and withdraw the circuit board from the lamp assembly, then refit the LED strip lights from the 1M piece you get off eBay, it has to be cut to length and I found the place where it has to be cut is the perfect length for the lamp. The LED strip is flexible so will need a solid backing so that it can be refitted, I used the old PCB from the lamp and de-soldered all the furniture and used it as a back plate to stick the LED strip on, once fitted a few drops of hot glue hold the lights in the right place for maximum light penetration through the clear plastic diffuser lens behind the red part outer lens.

It takes about half an hour to an hour to repair including soldering the wires into the car loom, I've never had the problem since and the light works great - brighter than before. There are two types of LED strip, one with more less powerful LED's and one with less more powerful LED's It don't matter which you use but I used the 3528 LED's in day white.

3528 5050 White Blue RGB LED Strip Lights Stick-on Tape and 12v Adapter Decorate | eBay

The car will still pass an MOT if you disconnect the light and tell the tester that it is just a reflector and not a functional lamp.

Hope this helps? better than £80+ for a new one!