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.
- Intermittent failure of windscreen wipers.
- Failure of indicator lights to flash when setting alarm via remote keyfob.
- Complete failure of all courtesy and footwell lights.
- 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 !)
- 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