High Visibility rear brake light

**s833son** · 22-11-2009,10:05 PM

Hi guys, had a malfunctioning rear brake light - the one on the parcel shelf - took it apart and resoldered the joints and hey presto all working again - worth trying if you have similar problems and cheaper than a new one !

**Micha_elD** · 23-11-2009,11:55 PM

I had a malfunctioning rear light, full of condensation, took it apart, dried it out, several of the LEDS didn't work. Resoldered them, some worked again, some were completely fried.

Think I must always have bought faulty soldering irons, everything I've ever soldered has stopped working forever.

**s833son** · 24-11-2009,09:37 AM

well thought I'd fixed it - worked for 2.5 hours yesterday am on a long drive - then failed on the way home with a Police car behind me ! Worked again this morning so am now very confused as there is only a diode, capacitor and 2 resisters in there and they are all fine so where else could this be failing - any ideas anyone ? Very intermitent and very annoying !

**Micha_elD** · 27-11-2009,09:18 PM

A problem with the wires leading to the light? Are they pinched anywhere?

**s833son** · 30-11-2009,09:06 PM

Hi all,
cant believe there is noone who has ideas on this !. I took the unit out and put it across a car battery and it works fine, the unit is great. Wiring all looks in perfect order - clipped in and looks fine. Disconnected the battery and still not working. Is there a sensor or anything or any ideas from the wiring diagram where these wires go ? Are they on a seperate fuse ?
Completely driving me mad !

**Micha_elD** · 01-12-2009,11:17 PM

But we're still having to guess what car you have; its impossible to help when you ask about wiring and fuses, when we haven't a clue what car you're talking about

**s833son** · 02-12-2009,12:59 PM

Apologies - missed that off ! 2005 (D3) A8L 4.2 Petrol

**RJS_90q** · 05-12-2009,08:19 PM

How do you know that the rear brake light is not working ? - do you rely on seeing a reflection in the rear window whilst driving ?

If so, have you checked that the regular brake lights are working ? - maybe an intermittent issue with the brake light switch stopping all the brake lights from working ...

Just a thought...

Regards
Bob

**s833son** · 07-12-2009,11:32 AM

Hi, thanks for the suggestion - the main lights are working - the high level one was intermitent and now wont work at all - you can see it in reflection or with observer. It doesn't show up on VAG-COM as any failure but that might be just the s/w I am using. Tested the unit again over the weekend and works fine with no LED's gone so might have to take it into a workshop

**RJS_90q** · 07-12-2009,09:46 PM

Okay- good info, so now a bit closer to the issue.
Based on this feedback of the high visibility brake lights working normally (when removed from the car) and that the main rear brake lights are working normally then it would seem that the wiring (or a damaged crimp within a connector) to the high visibility rear brake lights will likely be the issue...

If the situation where the high visibility brake light not working remains constant, is there a way of checking the voltage available at each the high visibility brake light connectors (at the high visibility brake light) by using a voltmeter? If no power is available - you will need to check the wiring to understand why... If power is available, check that there is a suitable earth path. Some caution here though - unless you are familiar with the car's electrics it is probably best left to a workshop...

Hope that this helps,

Bob