95 Jeep Grand Cherokee Tailgate Latch

first is diagnosis.
you examine and test it. to see if its electrical or mech. failure.
and once discovered that follow that to logical conclusions.

Hi,empty the boot,check for eney plugs or holes if none,
shut tailgate and get a hose-pipe and shower the car round the top part of the tailgate,quickly wipe off exess wateropen tailgate and see if there has been eney water getting in,if not open tailgate and carfuly so as not to let water go over into the boot turn the hose on to the lamp lenses where the sills are and see if water enter through them if not try be hind the petrol-flap,
my moneys on the tailgate sill.hope this helps

Review this reference documents: ZJ-Secc-8P-Power-Door-Locks (Page 4)

Good luck... and rated my help!!!

the most likely failure is the tailgate lock actuator, the tailgate will have to be taken apart from inside (very difficult)

I had the same problem. I was able to get the back window open.
I took the the 4 screws off that are on top of the inside of the door (where the tailgate window latch is).
Got a metal coat hanger. straightened it and made a hook at one end.
carefully pushed the plastic part of the tailgate towards the inside
slid the coat hanger straight down (to the level of the tailgate key/handle) to catch the door latch from the inside and pulled up.
that will get the tailgate open.
then you need to take the rest of the screws out of the lower part of the tailgate to get at the latch assembly. Carefully take the plastic off.
(you will need to take the nice black insulation stuff off the metal part of the door carefully so you can replace it and tape it up if necessary after fixing the latch.)
peel the insulation off the metal part of the door, you will see the assembly rod has come off the latch and will need putting back in place and a little sqweeze to stay on.
really bad design I guess, but since I fixed it at 140000, I haven't had any trouble with it at 166000.

This is kind of tricky. OK let's start, you have to crawl into the rear hatch area from the inside of the car. You'll have to pull the rear panel off the hatch, a screwdriver between the panel and hatch near the window will work. There might be 2 screws on the panel you could take out. The trick is to pull the panel far away enough to stick your arm down towards the latch and release it by hand. We did this at the dealer all the time.

The lock accuator on the tailgate is bad.

As you are turning the tailgate is flexing.
If you adjust the striker to get the tailgate to close tighter, it should fix your problem.

I don't think you need a wiring diagram.
Jeep had alot of problems with the lock accuator in the tailgate.

I had the same problem on my 94 grand cherokee! Try pushing in hard near the latch on the tailgate on the outside then pulling it open. I tried everything before stumbling on to this solution!! Lube up the latch and you should be fine.