2005 Audi A6 electrical problem

terminal. LHS

Would this account for the bulbs working for up to 15 minutes before going faulty?

Managed to get it on VCDS, error is an intermittent short to earth IIRC (the file isn't available to me at the moment).

I've had this problem before with a Passat, there are no leaks or damp patches I can find anywhere.

terminal. LHS

Yep

So the fix is a new bulb carrier (grey plastic unit with all the bulbs in it), the connector housing (the plug that goes onto the carrier?) and is the earth wire terminal on the carrier, connector or elsewhere?

Thanks!

Have you inspected where the problem is?

Just go to the dealer spare parts and ask them for the bits - tell them whats happened and they should put you on the right path, if their worth the salt.

I can't find a view on the web.

[...]

If it was my money, I would temporarily wire in an extra earth,and try it for a day or so.

Without know the construction of the cluster, it's difficult to be specific, but most of them have some sort of "busbar" system carrying the connections inside. If so, identify the earth one by inspection, and clean a part of the bar. Wrap a suitable piece of wire around the bar, and tighten a cable tie over the connection. Find a route for the wire to something that bolts to the bodywork to connect the other end to.

If the problem is a poorly-designed earth arrangement, replacing the cluster might only be a short-term fix. Certain BMW's have a similar design fault, and I have effected a cure on two cars now along the lines of what I have described.

Chris

The bulb holder has a clear layout making it easy to identify the earth, but it becomes a sealed unit before fitting to the car so I'd have to drill a small hole through it, solder the wire onto the bus bar and then find somewhere to earth it. There are no obvious earth points visible near the light cluster so I'd have to create my own - remove paint, drill a hole and then try to get a good connection to it. Tempting, but I'll also need to put a plug in the Seth wire to allow me t disconnect it in the future, to make changing bulbs easier.

[...]

My thoughts were more on a temporary method to see if it's an earth fault. With care, a reasonable 'Heath Robinson' setup will do that.

The alternative is the cost of a replacement cluster, which may not fix the fault, or may develop the same fault in the future.

You won't need to solder a wire; just wrap it, then use a cable tie to stop it moving. (One car I did this to was still OK after a year, although I emphasised to the owner it was a temporary repair.)

Without knowing the exact physical layout, it should be possible to get the wire out of the light unit without any drilling. (You only need something like 1mm2 to improve the existing earth.) It won't matter if the cable is squashed or trapped, after all! You don't need an earth point close to the light; anywhere would do although inside the boot would clearly be easiest. I would eat my hat if there isn't an existing earth point somewhere in there!

Chris

I'd connect a DVM between the cluster ground and a good car ground and see what the voltage drop was first.

I've cleaned up a bit of black from the earth terminal, and the car hasn't given the errors on a couple of short drives, so I'm fairly confident that this is the issue. I'm just wondering whether the new bulb holder, connector etc is the best solution - if it's an earth problem, unless the new connector etc have been redesigned (the bulb holder is a year old, it came with a new light cluster to replace a cracked one) the fault will come back eventually. Providing a second earth completely independent of the original, sometimes faulty one seems like a better long term solution.

Any opinions for and against?

On checking the connector today, there was a black mark on the earth terminal. Cleaning it off with a screwdriver has apparently resolved the problem, for now. Since its a known issue I want to try and ensure it doesn't come back at a less convenient time, like during the MOT :-)

A smear of Vaseline etc should slow it down corroding again - if it is corrosion.

Is a bulb failure warning on when all the bulbs work a failure?

[...]

AFAICT, the warning light system for bulb failure is not testable.

The OP implies that during fault conditions, the actual lights are not working:

"All the bulbs are ok and work fine before the errors come up, and start again immediately if the ignition is turned off then on again. Including (for example) the brake light coming back on as you turn the ignitin back on if you leave your foot on the brake."

which clearly would be a failure.

Chris

It looks more like the result of an electrical spark to me, but it's at a difficult angle to view close up. I'd say there's a very good chance it's the result of a bad connection.

The bulbs don't work when the failure warning comes on - when the warning happens, the car stops using those lights until the ignition is turned off then on again. The wonders of everything being electronic and intelligent :-)

If this happens when the bulbs are being tested. The lights may work for

10-15 minutes, then fail, so the bulbs may have been tested ok at this point - would the car fail the MOT for something that failed after it was tested, but before the final pass/fail was decided?

The message informing the driver about the bulb failure only appears when the lights have stopped working.

Further to this, bodging a temporary earth to the metal connectors inside the bulb holder seems to have solved the problem.

Thanks all for the advice.

Hi Simon

I have the same problem as you, but dont really understand what you meant by your fix? Would you mind letting me know a bit more detail so I can fix my lights too, photo would be perfect if not being too cheeky.

Thanks

Sam

I doubt you'll get a reply two years on, but it's a common fault on cars for the earth connection to a cluster to burn out as it has to take the current from all of the bulbs at once. Pull the connector off the cluster and it's usually obvious from the charring which one has overheated.

Bypass this by running chopping the wire off and extending it (or run a fresh wire from the bodywork) to the relevant bit of the metal spider inside of the cluster.