You'll need to take the inner door panel off.

Between the door panel and the door is a plastic moisture
barrier also. You can see where the access holes in the door
are through the vapor barrier. Don't remove the vapor
barrier, just make a hole in it big enough where you can
get in and work around.
When finished, take some packing tape and tape the hole back up... this will help prevent water from coming in contact
with the inner door panel It's not perfectly water tight,
but you want it to seal up as good as you can.

1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8