So you cant hear or feel w your hand on the hatch it locking or unlocking? Pretty sure there is a fuse for the rear hatch, but I think its tied into the rear door locks also. Are those working?
You can try beating w/ your fist around the edges of the door where the latch is.
If that doesn't get you in, I remeber reading someone broke the mechanism and they had to drill the trim/handle panel/pocket out, basically destroying it. I think you have to buy all this as a single piece anyway, mechanism included...
Easy Ed posted the service manual pages on this, but its w/ the door in operation.
http://i639.photobucket.com/albums/u...2/IMG_0227.jpg
http://i639.photobucket.com/albums/u...2/IMG_0228.jpg
http://i639.photobucket.com/albums/u...2/IMG_0229.jpg
http://i639.photobucket.com/albums/u...2/IMG_0230.jpg