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Audi A6 Leak and Electrical problems - mcrat26014

We have recently purchased an Audi A6 2.5TDi Avant, and the other day I noticed the carpet in the rear passenger footwell was very wet we have checked the door seals and they seem to be in alright condition.

And the other fault which I do not know if this maybe associated with the water is the other day we found all the indicator lights stuck on ( not flashing ) so called out the recovery service and the guy that came out started pulling out fuses to find out what was going as he pulled out the fuses for the hazard lights and turn signals and they still stayed on then he pulled out the fuse for the central locking, electric windows and boot light and the lights went off but the push button for the hazard lights was still dimly glowing even though the fuse was out.

Any help would be greatly appreciated.


Audi A6 Leak and Electrical problems - Bill Payer
Apparently common problem in A6's is the scuttle drain hole (which is underneath the battery) get blocked and water runs into the car through the heater vents.

This happened on my FIL's car and the auto box ecu (which I think is somewhere around the front passenger seat) got very wet and failed. Maybe there are other electrical units in the same area that might be affected.
Audi A6 Leak and Electrical problems - bell boy
apparently there is a box of tricks under the passenger seat that gets infected with water and gives your symptoms,i believe the water is a known problem and either gets there by the action of coming from the front or through the door card i believe?see your dealer these boxes arent cheap,it wants drying out soonest most people cut the carpet to get to it.Make sure im right first though.
Audi A6 Leak and Electrical problems - mcrat26014
The only place that is wet is in the rear passenger footwell with no water in the front passenger footwell and it is only the near side one that is wet also. Would this box be in the back footwells also.

Thanks for all your help
Audi A6 Leak and Electrical problems - bell boy
thats where they are if fitted.
Audi A6 Leak and Electrical problems - Bill Payer
The only place that is wet is in the rear passenger
footwell with no water in the front passenger footwell and it
is only the near side one that is wet also.

That's exactly the same as my FIL's car was, and it was caused by the scuttle drain being blocked. He has an engineering background and he couldn't understand why the front seemed dry yet there was water sloshing about in the back.
Audi A6 Leak and Electrical problems - Aretas
If the A6 is anything like the A4, then it will have heater vents in the rear. Therefore I guess it is possible that water entering the vent system will first show itself in the rear as they are lower than the front ones.
Audi A6 Leak and Electrical problems - simona6
Its all true, I had litres pour out of my scuttle (98 A6 TDi SE) when I finally unblocked the drain.

1) There is (or on mine anyway) another bung that can be pushed out which is much larger than a normal drain and stays more clear as a result.

2) The water in mine could be seen running under the seat, remember there must be channels for heaters and so forth under the front seats.

What may not have helped mine was the fool at the nameless indy "specialist" who coudlnt make the pollen filter fit properly and then left half the clips off the scuttle cover.

Ho Hum
Audi A6 Leak and Electrical problems - ubidenmark
Last year my well documented A6 starting acting like chitty chitty bag bang. Driving along the central locking would pop on and off, all the interior lights would come on, the windows would go up and down. Left in a supermarket car park, I came back to the car to discover the rear windows had lowered themselves in my absence.

After much research here the fault was diagnosed to the central locking control unit in the front passenger door cavity. It controls other functions too. The door cavity acts as a water trap and the control unit starts shorting after water contamination.

Naturally, the dealer promptly proposed replacing the unit. However, the car had sat idle for three weeks in a particularly damp period so I tried just letting it dry out. That seemed to do the trick and, touch wood, the problem hasn't recurred since.
Audi A6 Leak and Electrical problems - everything needs fixing
Long shot this - realise you havent posted for 4 years so this might be a dormat account. I have exactly the same problem (1999 A6) down to the indicators that wont go off until the fuse is removed. Understand everything about root cause, drains blocked under battery tray etc, but need to know what you did to resolve the water damaged component that was causing the indicators to stay on. Did you have to replace something specific or did drying it out do the trick. Mine are still on !!! The car is effectively undriveable as a result due to having no indicators. Any help from you (or anyone else with exact same problem) appreciated. Thanks
Audi A6 Leak and Electrical problems - Peter D
Your plenum chamber drain plugs are blocked up and ithe chamber is filling with water and eaither spilling over into the pollen filter of leaking through the pollen filter housing seal against the body work. Just remove the battery cover and look down the side of the battery with a torch. You will need the radio code as the battery has to come out to gain access to the two drain plugs that are clogged up with small leaves and debris. The front scuttle has to come off in front of the screen. The water is under the passenger front and rear footwells flowing backwards in the recess for the rear heating duct. Under the front footwell is the convience control unit and if water enters the unit or the cabling all forts of faults kick in, central cocking, interior lights, indicators, alarm issues. You need to get the CCM out and get it dried off and the connectors checked cleaned and lubricated. Goto www. VWAugiforum.co.uk/forum go into the correct section and search on Plenum chamber and all the instructions are their. There is also a photo set of instructions in the Passat section. Regards Peter
Audi A6 Leak and Electrical problems - everything needs fixing
I am much obliged to you for the prompt reply. Have just come back from leaving the car overnight with front carpets raised and miraculously the electrical problem has resolved itself. Let's hope the CCM itself isnt permanantly damaged and it is just a short around the housing/connectors. Have removed battery and unblocked that drain after which a small paddling pools worth of rain water flooded out. Had been dreaming about a 2nd-hand purchase of a 2004 RS6 but seriously unsure now!! Seems from other similar posts that I am very lucky to own a manual transmission car as the TCU is in the same location - seems that very serious and expensive damage has occured to other cars from this same bulkhead drain plug issue. Have been a lifelong VAG driver but have to be honest and say that the golden era of those cars was Mk2 Golf / Audi 80 years and since then they seem plagued with electrical problems (both front electric windows have failed previously on the A6 also due to mechanical wear). What's the point of the engine going on for ever if the rest of the car disentegrates around it!!!
Audi A6 Leak and Electrical problems - Peter D
Remove the CCM form it's case clean and dry it. If you leave it camp it could cost you £240 and even a replacment cable harness.

As you have only recently purchased the car can you not take it back under warrantee. Regards Peter
Audi A6 Leak and Electrical problems - everything needs fixing
I piggybacked on an old post it was them whose car was recently purchased. Had my A6 5 years. Got trim and carpet up, left heater blowing all afternoon has dried out most of the damage. Hooked CCM out, water poured out of it seems I was real lucky here that everything still works. Not looking foward to replacing trim, door rubbers and getting carpet back in place once it is completely dry, if my kids hadnt already destroyed the rear interior I might have been a lot more upset about the damage. Mould growing on the carpet is an interesting new AUDI feature I must say.
Audi A6 Leak and Electrical problems - Cservice
I soaked passenger seat with water, washing my car. And now the car won't start. tester tells me that is no voltage on section B of injection,this means 1 side(3 injectors),My car is a6 2006,132Kw,V6

sorry for my bad english

Edited by Cservice on 29/12/2009 at 10:14

Audi A6 Leak and Electrical problems - Neil Restick

Apologies for asking after such a long time but my A6 C5 2001 has had the common water leakage into the passenger footwell. Currently drying out but each time I connect the battery I get the same fault - all my indicators are lit. Worried that I will need to locate the problem and correct and not just keep waiting. Any info gratefully received.

Audi A6 Leak and Electrical problems - quattroguy

We've just had the same problem with our A6 Quattro. Theres a convenience box under the passenger side front floor, this could have got wet via a leak or spillage and wld cause these problems you're describing, if not too wet MIGHT be able to dry out, but may need to get another one.

Audi A6 Leak and Electrical problems - Dabooka

Nice advice, but you do realise this thread is a billion years old?!

Audi A6 Leak and Electrical problems - V4 Heaven
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