Rain Stops Play
 

Hi All,

My 2010 D3 LWB has an issue somewhere with water ingress.

It's been fine until Friday morning. On Thursday I'd done a 2hr drive down the M1 in heavy rain and high winds all the way. Car warned me my screen washer reservoir was low. Topped this up once I'd parked up on Thursday evening. Locked it and retired for the evening.

Friday morning, early hours, there was a car alarm going off outside. Mrs has an A4 which sometimes gets triggered by high winds. But neither of our cars had any flashing indicators so we assumed, given the swirling winds, it was from further down the road. Didn't seem loud enough to be ours.

Took son to school Friday morning, noticed the auto boot wasn't opening. Walking away from the car by school, a minute walking down the road, again I can hear the same alarm behind me. It was my car... :Confused: Again, no indicators, sound is more like a scratchy beep-beep - not the horn. It must have been mine in the early hours too.

As the car needs a service this week, I popped by my local independent on the way back from the school run, and he ran a quick scan for me. He said the scan showed a number of low voltage errors. Again, a minute after locking the car with the fob, the alarm goes again. The boot close button is lit but doesn't engage the motor, that is still not happening. The button inside the car pops the lock on the boot but the struts don't move.

He said there were no codes showing what was triggering the alarm, and he'll have the car all Monday for the service so hopefully can investigate further. But in the meantime basically I can't lock the car without p!55ing off all the neighbours.

I also noticed this afternoon when the Mrs was driving, that a small amount water dripped under the glovebox from the transmission tunnel side onto the carpet at the side of the tunnel. I felt underneath that side of the glovebox and it's a bit damp. Could that be debris in the drains?

I also had a look under the bonnet to see if there was any leaf debris blocking anything. On the bonnet hinge on the nearside, where there is an aperture in the scuttle fairing around the hinge, I can see a trunk of wires and a thin pair of wires, which also feel damp. That's not good is it?

Googling tonight, could it be that the sound I am hearing is not the actual alarm, but a sensor warning that the car thinks a door/bonnet/boot isn't closed properly or that the backup battery is on it's last legs (which might account for the voltage errors in vagcom?) I wonder if opening the bonnet to top up the washers let water into a "Bonnet closed" sensor? Again, it's not a massively loud sound, more of a crackly beep-beep - but perhaps I've never heard the actual A8 alarm for reference, as I've only had the car a few months.

I also could see last night that there was a lot of condensation inside the front and rear screens. So it's letting water in somewhere.

Just wondered if anyone here has had the same problems and can offer some advice? Other than "Put a lit match to it" ?

Sounds like your battery is weak. Some car alarms go off when the battery level drops because it thinks its being tampered with etc.

Re the water leak, it could be the windscreen leaking if its had one fitted. They usually join the two sealer beads in the middle (transmission tunnel area you mentioned). If it was leaking by the scuttle area/bulkhead then the carpet would be wet, and sometimes its too late when you realise that, the floor pan has a puddle under the carpet.

These are the wires that seem to get damp, by the passenger side bonnet hinge:

There are two drain hoses (one each side) that are supposed to drain below the car. If they get blocked, which they do very easily as they have a crimped lower end, water may build up and run down into the front passenger footwell where it drowns the electrics under the carpet - ask me how I know...

Sorted.

Turns out the plenum chamber was full of water and the siren was completely soaked (that is what those wires go to). These drains were unblocked and I had the heating on max and parked with the windows down at home all yesterday.

Now I need a new siren and a new battery. I know the battery has to be coded to the car too ;)

Water ingress to our cars is frustrating at best but can be expensive if not dealt with.

The plenum is a favorite and swiftly followed by a sunroof if you have one.

Then the AC drains also need looking at but less frequently.

Have a look at this video for doing the AC ones but by a set of clic r pliers from ebay first so you don't wreck the hose clips.

You should peel up the carpets also and make sure they are not saturated and sitting on top of a puddle of water around the phone module etc.

Also have a look through the common faults in D3 section for the drain threads, here's mine http://forum.a8parts.co.uk/showthread.php?t=9680