97 E230 Freaky Central Locking Problem.

[Mikesmerc]

This is a car I have accuired for my dad, trade price was good due to niggley little problems which most of I have solved but one. When I unlock the drivers door with the fob the boot pops open or when I go to get out with the drivers door auto-locked it also pops open. How can these two be linked. I know someone was fiddling around with the system as I found a vacuum type plunger wired to the vac pump but not hooked up with a vac tube(will take a pic later to show) and the fuse box modules were swapped around so you could not remove a line of fuses without removing half the casing.
Any ideas?
Thanks
Mike