A6, 2000, 1.8T, Water ingress, Wipers, Windows & other Woes....

Background...... Around 6 months ago, I reported on this newsgroup, deep water (about 7cm) in the RHS front and rear floor pan after a spell of rain. This resulted in
the loss of a considerable number of electrical functions, as follows.
1. Intermittent failure of windscreen wipers. 2. Failure of indicator lights to flash when setting alarm via remote keyfob. 3. Complete failure of all courtesy and footwell lights. 4. Failure of all electric windows.
Having finally resolved these issues I thought I'd share my experiences with the group.
How did the flooding happen in the first place? An inspired design ? Rainwater from the windscreen runs into a chamber between the engine compartment and the passenger compartment of the car. At the bottom of this chamber is a kind of rubber drain gizmo. This opens under the pressure of water to drain the chamber to the outside of the car. It's about 3cm diameter, fits like a grommet into the base of the chamber. It is sort of tubular but moulded at one end into cross shaped 'flaps' . (Imagine taking a flexible tube & pinching it in at the 4 points of the compass). I presume it self-closes to reduce road noise or fumes? Difficult to describe in words but you'll recognise it when you see it, or rather 'IF' you see it, as it is, in a stunning piece of AUDI engineering, tucked away out of sight underneath the battery which is housed in the same chamber. Knowing where it is, it is relatively easy to access and check that it it clear, and not, as I found to my cost, blocked up with a few small leaves. I realise this is not a new discovery, having trawled various newsgroups, but thought I'd try to impress on owners some possible consequences.
Procedure. Remove rubber strip sealing holding the plastic cover in place. Pull cover towards front of car and lift off .. Remove battery. Remove battery support tray. Discover drain gizmo, and clear if required.
I shall certainly be doing this annually from now on, in view of the pain of rectifying the consequences.
The chamber houses the battery, windscreen wiper motor, ECU, and ventilation air filter. It was full of water almost to the top of the battery after a few days of heavy rain. Once a certain level gets reached, water finds a way through the bulkhead into the inside of the car, which was the first I knew about it, getting my feet wet on getting into the car.
Draining the water out and drying the carpets was a right royal pain. Have you seen how thick and spongy the carpet underlay is? And I was left with the legacy of the faults listed above.
Rectification of faults. ( Omitting the dead end paths which were not the causes !)
1. Windscreen wipers. This was the last fault I rectified as it hadn't seemed to be much of a problem. I had just experienced a hesitation of the wipers to start on about 3 occasions, the first occurence being several weeks after the water ingress. They eventually (and embarassingly!!) failed at the MOT test station the other day, after working just fine the day before when I checked the car over. I removed the wiper assembly, extracted the motor to find a few drops of rusty water coming from it. Dismantling the motor revealed a wet and rusting armature. Rust expands, and I believe reduced the armature clearance to zero thus stalling the motor. Remedy was to dry the motor and clean up the armature with abrasive paper, lubricate and replace. I now have fully functioning & hopefully reliable wipers and an MOT certificate for the car.
2, 3, and 4, I can group together as they were caused by cable loom problems. The depth of water under the drivers seat (UK, RHS of car) was such that the wiring loom that runs along the floor pan just inside the door sill must have been submerged in water for a while. My initial thoughts were of short circuits, but it transpired my faults were due to a series of corroded connection points. That's right, more inspired AUDI design 'features'. Deeply embedded in the wiring loom you will find some 'connection points' where several wires feed into a crimp connector, which is then covered with a rubber boot and the whole loom wrapped in sticky black cloth tape. I found around 4 such connectors where the wires going into them had simply corrroded completely away. The remedy was to remake these joints. In addition to the corroded joints, I discovered one wire to have a break within its insulating sheath, with no obvious damage to the insulation. I can't figure out how this happened, but just had to splice that one.
Thanks for reading. I believe a little prevention is far less painful than the cure. and hope you all manage to "stay dry".
Ian
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How did you get the carpet out. I have had exactly your experience last week end except that it was the passenger side that flooded (appears to be the rear footwell). Failure so far are indicators, hazard lights and alarm going off ( had to remove fuse), electric windows). How long were connectors wet before you replaced them??
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I didn't remove it completely, just enough to gain access to the loom running along the front RHS door sill. The plastic trim along the door sill holding the edge of the carpet down just prises off. The seat front mountings are just a couple of nuts, accessed after again prising off plastic covers. This allowed the front seat to tip backwards enough to lift the carpet up enough to get firstly towels under there, then a hair dryer.

There doesn't seem to be much preventing water moving between the front and back. There is actually a "black box" under the LHS front carpet, housing an electronic module which controls the alarm, locking, windows, amongst other things. This is what I feared ( ssss) could have been blown on my car until I found the wiring loom failures. However, it did actually seem fairly well sealed and was dry inside in my car.

Just seems to be the window fault that is common. My alarm problem was just failure to blink the lights when arming / disarming. But of course the "connections" in the loom which I remade will not be the only ones.

The water could have been inside my car for a day or two before I used (or rather, came to use ) the car. I then drained the battery chamber immediately as well as removing all the water "above" the carpet. I then, mistakenly in retrospect, thought the rest would gradually dry out, and the faults go away. When you get to see the thickness of foam underlay bonded to the carpet and the ribbed type floorpan, you realise this won't dry out in a hurry. The foam is a gigantic sponge and water still slushes about underneath it. The faults were evident after the first couple of days from the rainstorms, though it was a month or so before I addressed the problem, and found the breaks in the loom.
Good luck in your efforts. Post again if you feel I may be able to help any further. Ian
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Ian G wrote:

<snip>
I've just returned from a rather wet weekend jaunt around Europe. Parts of Belgium were so wet, aquaplaning became boring. One particular piece of water on the motorway was so big and deep that it created a complete wall of water every time a vehicle hit it.
Last night we noticed the rear RHS footwell was very wet. Carpet completely soaked, plus a little water sitting on the top - but not the front. Thanks for posting this - it's given me a pretty good idea where to start looking.
--
Dnc

B1200 - +30bhp ~|~ ZZR1100 - faster when upright
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