Wiper motor install

[Scott4140]

I've searched high and low, FEP and google, and cannot find specific answers. Does anyone have pics or can point me in the right direction, no pun intended, as to how the wiper motor is properly installed, indexed? The vehicle is 1982 Mustang GT. The wiper motor currently installed never produced a full sweep of the windshield. It acted like it was installed incorrectly, but displayed a decent amount of torque. I took a pic of the motor's arm orientation before removal if that helps, I can post it, if necessary.
Thanks in advance

[JTurbo]

When I recently installed the wiper motor in my 82 GT, I installed the motor only as a first step. Then cycled the control on/off a few times to be sure that it had indexed correctly. After this was done, then I hooked the arm to the motor. Sorry I didn't take any pics of the orientation of the motor's arm....