Open glass of liftgate 2000 jeep grand cherokee

the hinged glass out....
the fsm factory serv. man. shows this.

chapter 23 , called heated rear glass.
page130 states
Disconnect heated liftgate glass electrical connector2. Open the liftgate and support.
3. Disconnect liftgate hydraulic cylinders (3) at the lower ball studs.
4. Close liftgate, but not latch in the closed position.
5. Remove hinge covers (1) and remove honge bolts (2).
6. Remove liftgate. unquote...

Hi Gloria, I'm glad to help!

Gloria, the most likely cause for no alarm when the liftgate is opened is usually because the controller does not see the liftgate open. 2 things can cause this. (1) The alarm switch on the liftgate could be bad. (2) The wiring going to the switch could be broken somewhere in the wiring. On the Jeeps its usually broken where the wiring is bending all the time between the liftgate and the body of the vehicle. If you pull the rubber insulator out you can then check the wiring. If the wiring is good then the next step would be to try an alarm switch for the liftgate. Hope this helps and have an awesome day Gloria.

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.

Check the flipper glass latch, maybe just sticking, lubricate it

You have to pull the panel off. It's going to be hard and you might break it

There is a switch, most likely built into the latch, that tells the body control module when the liftgate is open or closed. If that fails what you experience will happen. An open / shorted wire or bad BCM or overhead panel will also cause the "liftgate open" indicator to be on. Try and locate the switch and look for obvious damage.

yes

sounds like a defective liftgate latch assembly..ajar switch is part of latch..dealer item