A6 C6 Towbar problems


Registered User
Jun 13, 2012
Reaction score
Weston super Mare

I've just fitted a Westfalia towbar and electrics to the car (Avant) but keep getting a warning of "towbar not fixed". I cannot change, using VCDS, the long coding on the trailer part from Automatic to Retrofitted / fixed? Has anyone else had this problem or know how to solve it without going to Audi?

In addition all electrics work except the brake lights with the bulb out warning appearing on the DIS. Is this linked to the problem above?

All other coding went fine and it's all properly wired up with the rest of the cars electrics OK?

Any help would be appreciated!


Are you sure that you wired the brake light wire up correctly as when you look at the fitting instructions the wire you use is different on the avant and the saloon. I nearly made this mistake when fitting mine.
I think so, it was labelled as the Red / White wire in the guide. What did you find was the correct one - are you using the genuine audi connector or a bypass kit?

It is beeping that the bulbs are out when the brake lights are applied so I assume it's correct?

Thanks for replying!
Hi there.
On mine i purchased the whole kit used, but it is a removable witter tow bar with the A6 dedicated electrics and the split charge relay control too onto a 13 pin euro socket.

All i had to do was wire a couple of positives and earth's then the one wire onto the brake lights and the two wires onto the can-bus control as is standard in all the dedicated wiring kits from anywhere.

As soon as i fitted mine it came up with abs fault and my cruise control would work but the brake function on it didn't work. I had no brake light warnings. When the nice kind gent did the adaptation to the abs and the camera and the park control there was still no brake light faults. Have since towed my caravan from Scotland and all works.

Did you disconnect the battery when you fitted all the wiring.

I will find the details of the nice man that coded mine as he was very knowledgeable and I am sure he will be able to help.

The man is b5nut on here
Cheers, would appreciate that.

I did disconnect the battery and had the same faults you describe until I coded it. Brakes work fine, cruise etc. The only lights that don't work are those on anything connected to the Towbar! Side lights and indicators are fine!!!

I do have a 13-Pin to 7-Pin converter, I wonder if that is causing the problem!

Thanks though, appreciate you trying to help!
Fixed it! Two things were wrong, first workshop code has to be a number, not just 00000 when coding :whistle2: and the bulbs had gone in the brand new trailer part! All sorted now and happy!