Just finished re-installing my fan assembly an hour ago. There were two wires coming from the motor and a label on the motor stating that the "orange wire is a ground and the black is power. If I want to reverse the motor I should just reverse the wires". I did attach the ground to the heater case under one of the screws which holds the core to the sheet metal. This is the way the unit was when I bought the truck. I had it apart because of a leaking core.
