Outer Limits 4x4 Board

Hi all,
I've just bought a late 80's Pajero and two questions to start off with.
On the ground in the middle of the back seat there is a lever labelled open/close water schute or something similar. This leads to a meshed cavity under the back seat that contains something that looks like some kind of filter or radiator. Could dint get the cover off to have a good look. Any ideas what this is and what it does?
Secondly is there a decent vin lookup resource that will give me some more detail on the car somwhere on the web? being cheap I would prefer something free

Had a look at the water gadget and the label says "water valve" "open" "close" with a lever sticking out that can be moved between the settings. Had a look underneath the car but couldnt really see anything as it is starting to get to dark and the 3yo daughter has had the torch

I just googled for pajero "water valve" and came up with quite a few good pages.

It appears that it might be a rear heater?

Hope that helps

Blake