I would like to replace the window regulators and electric motors in my 1972 911S with regulators and motors from a 1974-1976 model. The newer regulators are a bolt-in replacement for the old regulators. However, the newer motor has two wires (green and black) compared with three wires on my original motor (green, black, and brown). The three wires from the original motor connect to a wire harness in the door. The window switches also have three wires (all red with black, white, and no stripes) coming from the same wire harness in the door.

My questions are: can I replace the early motors with the newer motors? Is there a problem if there is no brown ground wire connected to the harness from the newer motor? Will the original switch still work if I leave the three wires connected to it or do I have to change something? Is there anything else I need to do to replace the original motors with the newer motors?

Thank for helping!

Guy