2004 V10 Battery Draining Issue

Hi,

Being new to modern cars I took up the challenge and purchased a 2004 V10 Touareg and hgad it for about 12 days now. The day i picked it up the main battery was flat but by using the key it started first go. I test drove it a fortnight beforehand which was alright at the time.

The previous owner seemed to know nothing about keyless entry or keyless start. always used the key. He had it at the local VW dealer and an independant auto electrian for weeks to try and fix the clock resetting and the fuel averages resetting when starting the car. VW replaced the alternator which did not seem to fix the problem.

Since obtaining the car i charged up the main battery under the seat but it was beyond holding any charge. 2 days on a 10 amp charger and a load test brought it down past 5 volts. Replaced the battery with a new one and off i went. i do a fair bit of diring during the day and leaving around 7am and getting home 10pm with intermittent trips during the day started first time every time. Doing research and reading many things over batteries and drain i did upgrade the cd navigation from firmware 0629 to 0635

I came home early on a friday around 4pm and didnt work saturday. About 2pm saturday Tried to start the car keyless and all the electronics died as it cranked over. The battery was flat again. Swapped the battery with a smaller one i had from antoher car and put the big one on charge... which load tested fine on sunday morning.

The temporary battery was flat sunday morning. i then replaced the battery again with another full one and tested the vehicle according to the tsb on battery drain.

I bought the VCDS but still awaiting to obtain schematics for this vehicle

I checked every fuse 3 times on both sides of the dash and under the bonnet. I left an inline ammeter between the battery and notcsed the current being 2.5-2.9 Amps and occasionaly it would drop to about 0.1a for half a second but then back again to 2.5-2.9..for 3-10 second intervals.

I observed some fuses showing current on and off... notably Parking sensors, Tyre Pressure monitor system, Radio and a few others.

I then also heard a clicking noise of a relay every time this happened.

Finding the offending control box I found a box labelled "Bordnetzsteuergerat" 7L6 937 049 L which seemed to click and all these things turn on and off repeatedly. Unlocking the doors and ignition and the clicking stops.

First time with the VCDS VAG-COM software the only error I found on this control module was a 00907.... battery low which I would expect with the number of battery charges and swaps I did over the weekend

Watching the inputs that I could see on the VCDS I saw nothing unusual. I learnt I had heated mirrors that was on but that’s all!

The software won’t show you what the box is doing when the ignition is off so I couldn’t monitor the inputs.

Any ideas and what else this module controls or what it listens to when sleeping?

Or something else to look for?