2012 grand cherokee/ tail gate not working can it be opened manualy m the electric is not opening it

SOURCE: tail gate

this is a partial solution. Remove the inside panel on the tail gate -- simply remove several screws and pop off the panel. yes, you might break some plastic clips. That exposes the locking mechanism and it's a simple matter to open the tail gate from the inside now. See the rod with the threaded fitting? Unfortunately, I haven't figured out how to adjust the rod that operates the lock, so I've just left the inside panel off for now ;-)

SOURCE: 1997 Grand Cherokee. Tail gate wont open. Handle

These rear hatches have a cheesy rod and clip setup. You have to remove the panel from inside, you have to loosen the screws around the hatch and pull it away and reach in down toward the latch and open it that way so you can get the 2 screws out of the bottom easier. There is a peice of plastic in these that's a dust barrier, try not to tear it up too badly, and when you go to put it back, I use a spray adhesive to stick it back on while I put the panel back on. after you get it open you will see a rod with what looks like threads hanging there attached to nothing, and a little thing that has 2 notched areas and a clip to hold that rod into those 2 notches. bend the clip down to make it tighter and then force the rod back into place that should fix your problems. If that's all in place then it's the latch mechanism, usually they can't be fixed because parts aren't available, just have to buy a new one and put it in.

Testimonial: "Thanks very much, I'll give it a try. It's a bugger getting the inside panel off, I tried a few times unsucessfully."

SOURCE: Tail Gate of a 1996

That's a chronic problem with those. As the vehicle travels down the road, vacuum is created that draws salt and dirt into the tailgate and the latch mechanism rusts up solid. The only good way in there is to cut a hole just to the drivers side of center, about five inches above the floor in the inside cover You will see a rod that goes between the lock and latch. Either the rod has fallen off or the latch is binding (or both). Spray the latch with a good solvent and pull on the rod and the latch should open.
Usually, if you work it back and forth by hand, you can free it up. If the rod has fallen off, put it back on and use JB Weld putty, to secure it in it's holder. Inside covers are easy to find cheap at most local scrapyards, or, you can make a cover for the hole you made.