2009 Audi A6 C6 Brake Light Intermittent Issue

GreeBo

Hey,

In the last few weeks I have been getting a warning on the dash about drivers side rear brake light fault. Upon inspection the bulb is ok, it actually works fine for a couple of seconds when the car starts but will then die and the error appear.

Some googling led me to a likely earth/ground issue so I disconnected the plug from the CB, did some light scraping and used some electrical cleaner. This made it better (it stays lit for longer) but still ultimately fails.

I then split the earth wire and joined a 3rd wire to an existing grounded bolt on the body.

Again this has made it better, but not 100 solved.....any ideas?

I suspect possible corrosion on the bulb itself but cant for the life of me see how to take the unit apart (its the light cluster that is part of the boot lid) I can get the whole thing out but cant open it and reluctant to break it!

GreeBo

Oh and as a guide for any others, be warned that if your ground/earth works loose then you are in trouble. The car wont lock/unlock, fob is useless and the boot wont open.

I managed to climb into the boots via the backseats and reattach the wire :(

Kenny Logins

Have you tried a new bulb?

mk7r

Are they not led? So replacement of the whole light unit is necessary

GreeBo

https://www.boards.ie/discussion/comment/120465703#Comment_120465703

While I can get the unit itself out, its not obvious (to me!) how to open it without breaking it. The bulb is fine, it seems like a corrosion problem that gets worse when it heats up.

https://www.boards.ie/discussion/comment/120467696#Comment_120467696

No, the section in the boot lid is not led, the ones on the rear panel are led though.

cml387

I'm afraid it's likely the fault is internal to the light unit and full replacement the only option. I see quite a few failures of LED DRL's around nowadays and I wonder is the quality of soldering internally is up to snuff.

Kenny Logins

https://www.boards.ie/discussion/comment/120467914#Comment_120467914

Mk2 TTs are well-known for insufficient earthing on the rear lamps which leads to a burnout in the connector. The fix is to run a new earth wire from the lamp unit to ground.

GreeBo

https://www.boards.ie/discussion/comment/120467926#Comment_120467926

Yeah, thats what I want to do, just cant get the lamp unit open (Its off the car) some gentle prodding at what appear to be the plastic connectors/lugs didnt lead to anything and I dont want to force it and totally knacker it.

mk7r

https://www.boards.ie/discussion/comment/120467943#Comment_120467943

Post a pic because the c6 I have here has led inners