[Zoomad75]

Turn the lock with the key. Thats the way you lock the rear of the blazer up. When locked the crank is disengauged from the regulator, so it just spins. This way with the window up the rear is essentially "locked" without needing any other locking mechanism.

I will say it was smart of you to lock it with the top off to keep anybody from rolling the window up on you and breaking it with the top off.