Power Window question

I have a 98 Altima and a perplexing problem with the passenger side power window. The window will go up but not down. I've made sure that the regulator works free. Changed the motor. And, checked it by hooking it directly to a battery and it works up and down. There's power to the connector in both directions. When I hook the motor up to the connector, it only goes up. With the window up, when I push the up button, I can hear power going to the motor. When I push the button to make the window go down, there is only a very faint sound (like power getting to the motor) but the window does not move. I've checked most everything that I know to check and it all indicates that the window should work but it doesn't. I even changed the relay under the hood with no success. Should I be checking something upstream? REALLY a puzzling problem. Any help would be appreciated. Thanks snipped-for-privacy@execpc.com