I'm making some assumptions here since we don't know what system you have. Pictures would help, particularly of the motor and switch wiring.
Did you replace the switch? If yes I would think that the new switch is the problem.
Here's the wiring diagram for our door switch. Battery power comes in on the center switch terminals. When the rocker switch is pressed down the polarity is minus on the right hand wire going to the motor and plus is on the left wire. When the rocker is pressed up the polarity reverses to the motor terminals. It took me a while to figure this out!
First thing I'd do is check power to the switch to rule out a blown fuse. If power's good put the wiring back the way it was, including the old switch, then try the driver's door switch. If it works then you need to puzzle out the outer switch wiring. Getting the right replacement switch is key. A simple on/off switch won't work here.
Here's a link to the proper switch - http://www.elecdirect.com/product/4331f ... 4a092.aspx