The e30 has a problem with water finding its way into the car.
This could lead to a moldy smell as well as rust.
Potential sources of water getting the truck are,
Late model or early mode its the same procedure.
unscrew this round clip to remove the rear tail light housing for the bulbs
undo the 2 clips for the harness connector.
and remove the 6 x 8MM nuts
dont loose the bracket 1 per side
the tail lights just pop off the body once the 6 nuts per side are removed.
next step is to remove the rubber gasket. and install the new one.
the new gasket almost seams as if its too short but keep at it.
now is a great time to clear the rear end and wax it to.
old seal on left, new seal on the right.