Stop alarm sounding when battery is disconnected

I leave my camper van parked-up for a month a time.

In the freezing cold weather, there isn't quite enough juice to start it when I return to it.
I repalced the lead-acid battery with a new AGM battery but still get the problem (almost enough power to start the engine but not quite enough :( I'm guessing there's a power drain somewhere).


I bought a decent quality battery disconnect with the aim of disconnecting the battery and locking the van with the key only... that all works fine but when I go to unlock the van (with the key) the alarm goes off (the alarm has a battery backup).

The problem is; I always collect the van very late at night (2am) and it's parked right infront of a row of houses (rented parking space).

Is the only option to pull certain fuses instead, so the majority of equipment is disconnected but the alarm still gets power?

Cheers
Al

You can disable the siren with a diagnostic system such as VCDS.

Thank you

Hi Crasher, do you have any details disabling the siren please... any guidance as to which module / value to change please?

Which diagnostic system do you have?