Electric tailgate window question

[drkyello]

i have been looking for a electric tailgate for my blazer and have ran into a few at the junk yard, but i am not sure if the window motor works, or the window is rolled all the way up and i cannot bring the window down to even open the gate. is there a way to roll down the window without hooking up a battery to the car? if i connect a car battery to the wires direct to the window motor is it too much volts? any help would be appreciated