Ok here's the guide for an S3 with the Bose sub:
I was suffering from the occaisional 3 beeps from the back of the car and also the following error in VCDS:
01134 - Alarm Horn (H12) 01598 - Drive Battery Voltage 077-10 Signal low Intermittent
First off open the boot (obviously) and undo the 4 torx (size 25) bolts inside the boot trim near the warning triangle:
Next up you will need to unscrew the 2 torx bolts (size 27) that are under the spring clip of the luggage net holdings. There's one each side:
You can then remove the bottom part of the boot trim:
Now remove the side panel that lets you into the compartment above the passenger side rear wheel arch. If you look in and up towards the rear light cluster you should see a screw head that's holding a bit of plastic trim, like so:
As you can see I have broken the plastic at some point when I forgot about this screw!
With this screw out just grab on tight and pull at the trim and it will come away:
Now I found things a lot easier if you put the passenger side rear seat forward and lift the carpet. Then undo the luggage net clip that is behind the passenger seat:
Now move the central locking pump out the way, it might be cable tied in so cut the tie. With this out the way you will be able to access the bolts that hold in the sub as seen in the following pics:
Undo the 3 bolts (8mm I believe) and unplug the sub:
You then need to undo the bolts holding on the little amp for the rear speakers that sits above the sub:
This will then swing out of the way:
You can then swing the sub out the way too:
The siren is tucked down real low below where the central locking pump was originally:
There is one 10mm bolt that is on a brass bracket, undo this and you can slide out the alarm siren on the bracket:
With the siren out I set to work on it with a junior hacksaw. I didn't have any cutting discs for the dremmel and I thought it would be a lot more controlled with the hacksaw:
Unfortunately the batteries had already started to leak and the damage was quite bad but I had a go at repairing it anyway. The tracks on the board were also damaged from the acid:
I set about following the guide above and wired up the batteries to the board after a little clean up of the acid:
I put the alarm casing back together and taped it shut, reconnected it to the car but it is now a silent alarm
MY error message has now cleared though so the batteries were definitely the cause but I think the board tracks were too damaged. New alarm module time for me.
Hopefully you can catch yours before it's too late!
For anyone wanting the original part number here it is:
