I have noticed that a lot of people have had the same rear latch problem that I had last year. Mine is a 95 2 door Blazer and I am not sure if the glass latches the same way on the 4 door models, but this is what I did to fix it with very minimal damage to get glass open and repair.
The first thing I did was from the inside in the back, I pulled the cover panel back from the hump at the top of the interior panel. This will snap the plastic around the scew that holds that piece in place, BUT it will have little to NO affect on the panel. You will see 2 nuts holding the outside handle to the glass which also has the grasp for the window latch and guide pin. I used a box/open end wrench to remove those 2 nuts (one has the guide pin built into it) and my glass was freed so I could open the glass and then open the lift gate.
Now you can begin the repair for the broken latch acuator and by the way, when you go to the dealer to get the part you need, it is called the "actuator" assembly and you have to buy the whole assembly. I think it was about $50.
Remove the interior panel from the tailgate, it has a couple of screws and it snaps off around the edges. Now you have a large black plate to unscrew (about 12 screws) to remove and this will expose all the mechanism inside the gate. You will notice a bluish green PLASTIC clip that is broken. Can you believe they made it out of plastic? This clip pulls on a metal bar when you push the button to open the rear window. Dont bother trying to fix the plastic clip, it is useless because there is too much pressure exerted when the actuator is engaged. You will notice that there are a few screws holding the actuator and clip in place inside the gate. If you get the actuator/clip assembly from the dealer, you can remove the clip part from the new assembly without having to replace the whole actuator. So you are buying more than you need, but it is the only way to get the clip from the dealer. Once you see the inside of the gate, you will get the idea of how it all works and it is pretty easy to repair. The hardest part for me was figuring out how to get the glass open without breaking something like the glass itself.
Re-attaching the handle and gasket to the glass is very simple now that the glass is open and you can line it up with the marks from the dirt under the handle. So don't clean the glass under the handle so you can line up the metal grasp and guide properly.
I hope this helps, it has been over a year since this happened but I think I remembered just about everything.

 

Readers please also refer to related forum link https://blazerforum.com/fb.asp?m=91743.