trunk release

My 91 Passat has what looks like an air controlled trunk release mechanism, but there is no switch for it that I can find. There is an open spot for a switch in the centre console, but does not seem to be a connection for anything. It is a pain to have to use the key all the time. I have no manual for this car so no idea if there is anything to release the trunk.
I have not been able to find info on the web anywhere.

is it a bright green tube? if so it's your vacuum operated central locking.

It is a black tube that runs from the trunk latch to the DS and disappears behind the trim. I am unable to find where it goes to and no buttons in the glove box or on the dash except for one missing slot with no connector I can see.

I think the way it isupposed to work is that when the doors are unlocked the trunk is unlocked. So if that is not happening, then maybe the trunk auto lock is not working. That could eb a vacum leak in that tube you see (mine is black as well, not green as described above).

I will pop the drivers door off and see.