Help! What's that in the cupboard!

In my VW T4 Trooper. A lovely 1994 model there is a box in the second drop-down cupboard below the sink, next to the fridge. It is carpet covered with a 0/1 dtoggle switch which when plugged into the mains and switched to 1, a little green light comes on!

Is it a leisure battery charger? Obviously the fuse box is somewhere else as is the electrics panel on the 'wall' above the larder cupboard. So what is this mysterious box?

It's not in the original AS model booklet that came with the van when I bought it.

Hope you can help!

Welcome from Stratford-upon-Avon (on tour).   
Can't say for sure what that box is as I'm not familiar with the Trooper but a guess would be the charger. I'm sure someone will be along shortly to confirm if correct me.

If you don't have access to a voltmeter, try plugging into EHU, switching all the habitation lights on, and then switching the little switch on and off.

If the lights brighten and dim appreciably, it's the battery charger switch.

Welcome to the forum from Barnard Castle on tour

Sorry, can't help with your query.

Hi and welcome to the forum from Bridlington 
Boaby

Cheers Boab!

Thank you all for the replies!