On left of steering wheel on wall is a "button" to press, then in the backseat area, there is a "cord" that pulls the trunk loose also, it is near the top left hand side of top of seat. May have to dig it out.
The 1999 Buick LeSabre was a popular car for its time. The trunk release latch is located on the lower left hand side of the drivers seat.
Hire a mechanic!
If the 94 LeSabre trunk does not have a remote release, check the rear sear to see if the back is removable, to gain access to the trunk. If there is no access, then either a locksmith will need to pick the trunk or you will have to drill the trunk.
The socket size for the trunk tail light on a 2001 Buick LeSabre is 7mm. Bulbs can be purchased at most local automotive repair stores.
The spare tire is under the carpet in the trunk
Should have an access panel inside trunk
The trunk
try taking out the back seat. that is how i got into my 84 buick lesabra to unlock it
3.8 or 3800? 4.5 quarts with filter. About eight cases in the trunk.
I think the light assembly screws out from the inside of the trunk.
Remove the power trunk release, it may be stuck and holding the latch to the open position. I had same problem and found that if I use the key to unlock power lock then closed trunk - it worked.
If you have an automatic release like I had on a 1994 Buick P.A. and it stopped working and would not close, I had to replace the latch assembly to make it a manual by getting a used one from the salvage yard. The trunk still closes today.