Two ways I can see.
1.Pull the vertical covering in the front-most portion of the Boot(Trunk)
'looks like grey felt,it's fairly stiff so do not just jerk it out.Look up
You'll see a white hard plastic vacuum line with a blue stripe going
from each headrest actuator (looks like a thick black hockey puck)
over to a pass through grommet on the driver's side.'Just before
the grommet is one of the "F" shaped rubber vacuum connectors.
Apply a vacuum to the single port on the rubber connector(after
you pull the hard plastic line out). EASIEST
2. Remove the rear seat backrest(after removing the seat cushion)
find the white hard plastic,with a blue stripe vacuum line passing
through the rubber grommet on the driver's side from the lower trunk.
Pull it loose from whatever black rubber connector it feeds into in
the passenger compartment and apply vacuum. LESS EASY

OR, buy a MityVac (Vacuum/Pressure Tester) [Auto Zone,Harbor Freight]
and diagnose + fix whatever the P.O.'s wrench turner botched up.