High-level brake light

[porty]

Has anyone had problems with the high-level brake light on their B8? About 3 months ago, an error message came up on the dash when I braked that the centre brake light needed attention. I looked in the handbook and this is a light which is suggested that the dealer changes. The problem was intermittent and so - sods law - when I took it along to the dealers it was fine and they couldn't fault it. Every few weeks the message appears. I often find that the brake light is, in fact, working, and that the fact that the error message stays on the dash until the ignition is next turned-off is just to make sure you've seen it. It has just done it again today. I guess the problem is one of two things - the light unit or the wiring to it. Is this a common problem? My car is 6 years old next month.

[fat controller]

Not sure about the high level ones, but I had a spate of working then not working then working again rear lights (brake, tail, reverse and indicators) - - in the end, I lost the rag and replaced every single bulb and the problem disappeared. The only thing I could think that it could be was the bulbs beginning to fail and their resistance increasing slightly; I presume that the canbus measures the resistance across each light and declares it as duff if the resistance is higher than a certain value?

[Bonzo67]

Not sure about the high level ones, but I had a spate of working then not working then working again rear lights (brake, tail, reverse and indicators) - - in the end, I lost the rag and replaced every single bulb and the problem disappeared. The only thing I could think that it could be was the bulbs beginning to fail and their resistance increasing slightly; I presume that the canbus measures the resistance across each light and declares it as duff if the resistance is higher than a certain value?

Not quite Audi but. W discovered on the Range Rovers & Discoveries that say Halford or other accessory shop bulbs would throw up faults.
Only non LR bulb had fitted was PIAA in the main beams & LED in front side lights, otherwise all exterior bulbs were genuine LR/ dealership supplied and never an issue.

[fat controller]

Thankfully, I only use Bosch or that might have been another headache

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[hman_01]

Had this on mine and the fix is simple and free ( so long as you own a soldering iron.

Remove the rear light ( Audi A4 Third Brake Light Removal and Install )

warm up the soldering iron

apply the soldering iron to the solder at the base of the two incoming connection posts where they meet the pcb

Wait until solder melts

remove iron -

repeat for 2nd connection post solder joint

re-install brake light

job complete.

Mone was giving the warning everytime the rear window had the sun on it - it was the heat expanding the dry solder joint and creating an intermittent disconnection.

problem solved

[porty]

Many thanks for this. It's not something that I can do myself, but it is something that indicates there may be a cheaper solution to having the dealer replace the whole lighting unit which I understand may be expensive.

[benjie]

I replac ed mine a few weeks ago on my 6 year old, brilliant red S4 avant(!) but the light had been on the blink for ages. No error messages. I had 1 led out in the middle and it drove me mad. My money with you is a connection rather then the light unit itself.

It's a pain in the **** to replace, the trim needs bending back, screwdrivers need to slide a locking mechanism to the open position and the it comes out from the outside. I did it in 20min. I wouldn't want to do it again.

[hman_01]

Maybe a pain on the avant - but the saloon just slides out and sides back in - CLICK = job done.