i have a 99 grand cherokee and i noticed my back door hatch dont lock. If i lock all doors from the door panel on the driver door it locks everything but the back hatch and i have the keyless remote also it locks everything but back hatch. does anyone know what that could be? I looked and dont even see a manual lock on the back hatch

 

I have the same issue too. It seems i'm not getting any power to the switches/ solenoids for the lift gate and lift glass. Either it's broken wire or no signal from the body control module. I have no clue what wire it is to test for voltage. Need some wiring guru's

 

Could be a bad lock solenoid or broken wires between the gate and body in the rubber boot. Pull the panel off of the lift gate and use a test light to see if you have voltage at the solenoid when hitting the lock/unlock button.