I have a 90 honda 4 door civic. The driver rear window will go up but wont go down. It has power to the window. I have a brand new motor. Changed the switch to one i know works. I have the motor out of the car so i know its not ina bind so i am lost on what the problem could be

 

You seems to fix my 1st 2 guesses, now I would check the connections and wiring. I can't imagine it would be anything else since the motor is new and the switch replaced. Le us know what you find.