Trim - the cardboard-backed lining of the trunk. BUT, now that you explain that, it sounds like low fluid in the pump, which implies a leak somewhere. It is usually easy to find a leak by manually moving the top and looking around in the top stoarage area.

And do not be so sure you dont' have that tool, every car came with one. Search: Glove box, console compartment, bag hanging between the seats and in EVERY pocket under the trim / mat in the trunk!