I had the same thing on my 98 QC. Rear passenger door as well.
On my door the lower latch mechanism was seized and I had to use a 10lb dead blow hammer to force it open, then remove the door panel to get all of the linkages off.
From the underside of the door are 3 flat head machine screws, all of which sheared off while trying to remove them (also seized). I removed the latch mechanism and replaced it with one from the wrecker.
Not a very fun job, but best of luck with it,
HP