Mechanisms wear out, it's only a matter of time.
As it so happens, my rear lift gate release mechanism (the thingy that allows you to open the rear gate) stopped working, or was at the very least being very temperamental.
I've been in the doors of many vehicles, and am familiar with how all the rods, and levers, and linkages all work.
So I figured that the mechanism that latches the rear gate closed, and releases to allow you to open it, would have SOME sort of adjustment to it, and if it didn't, I was going to make it.
Here is a write up of how I adjusted it on my 99 XJ, (this should be pretty much the same for all 97-01's, I cannot speak for how it is set up on older Cherokees.)
There are several Phillips head screws that hold on the interior panel on the rear gate/hatch, it is easiest to get to all these, and to remove the panel with the hatch open,
if yours is stuck closed you may still be able to do this, but it may be a bit more cumbersome and time consuming.
Once all the screws are removed, there is only pressure clips holding the panel onto the hatch, use a panel popper, or light force with your hand to remove the panel a little at a time.
Once off you'll have access to the inner workings. The large opening to the right of center is where you'll be working through:

Using a smaller flat head screw driver, or equivalent tool,
Slide the retaining clip off of the linkage that connects the handle/lock mechanism to the release mechanism
(mine was green yours may be a different color.)

You'll want to apply force from the right to the left to remove the clip, it will simply rotate off of the linkage with a little pressure:

Once the clip side of the retainer is off of the linkage, pull/pry the end of the linkage out of the retainer all together (it should come straight out)

Now that the linkage is free, you can make the necessary adjustments. In mine, it is set up so that as you rotate it, the threads engage a forked clip, and will move the rod up and down accordingly.....
I adjusted mine all the way up (so that the majority of the threads would be protruding above the forked clip) - This gave the handle much more leverage on the release mechanism.

Now that your linkage is adjusted, it may be a good time to do some up-keep on the actual release/latching mechanism.
There are three Torx head screws holding the mechanism in place in the hatch.
Remove these three, and the mechanism can be removed from the hatch as a whole.

In mine there was a small wired connector/sensor attached to it. This is easy to remove and there is plenty of slack on the wire to do so.
This mechanism is not a serviceable part, in the sense that you cannot take it apart and replace anything in it.
You can however spray it down liberally with lube, blow it out with an air gun, and grease it.
This is what I did before re-installing it, and putting everything back together.
The assembly process is reverse of the un-install:

  • Re-attach the wired plug/connector to the mechanism.
  • Re-install the mechanism,
    -(its a good idea to tighten the two flat head Torx screws FIRST - the countersinks that these go into will help ensure the mechanism is centered in it's location)
  • Push the linkage securely back into the retainer.
  • Rotate the retaining clip back onto the linkage rod.
  • TEST the operation.
    -(If you need to make any adjustments - the panel is already off, and you will have easy access)
  • Re-install the interior panel - make sure not to over tighten the screws, as the plastic can break.