I'm the idiot transplanting an '01 XJR into a Mark 2. In order to fit the power window mechanism into the door I need to power the motor to the down position. Looking at the wiring diagram it looks like the motor sees either power up or power down from the orange and blue wire, but when I ground the motor and power the leads nothing happens. Is there a simple way to operate the motor or do I need to hook up and power the control unit? I'll appreciate any thoughts. Here's a pic of the XJR mechanism replaced with the shorter Mark 2 one to fit the smaller rear door. Thanks.

 

Try power on one wire, and ground the other one. If that doesn't work, reverse the leads.

The wiring diagrams don't show a ground, so they probably do it as above and reverse the polarity to drive it the other way.

 

Rob, you were correct. Thanks again.