rear lock problem

[blkjimmy]

Hey,
I have a 97 jimmy and a couple of weeks ago I noticed that the back hatch no longer locked when i put the key in it and turned it, or when i hit the power locks from the inside. However, when I turn the key in the rear lock it does lock and unlock the other 4 doors like it is supposed to. The problem is that whether all the other doors are locked or not i can still push the rear lock cylinder in and pop the glass hatch. I have taken tailgate apart and believe that the problem is in the electrical (housing, or switch? not sure of name) that surrounds the rear lock cylinder. Auto part stores don't have it and dealer wants about 90 bucks for it. He says he's never heard of my problem before. My real question is does it sound like I am on the right track with this electrical housing thing?
Appreciate your time.
-Doug

[old_master]

Can you hear the lock actuator motor operating in the tailgate when locking and unlocking the doors? If so, there is a linkage part that connects the actuator to the lock mechanism, it has a habit of breaking. If you can't hear the actuator operating, take the trim panel off and check the electrical circuits to it. There are two wires to the actuator. To make the actuator lock, battery voltage is applied to one of the wires and ground to the other. to unlock, the polarity is reversed.