I know this is an old thread, but maybe you haven't sold it and I've dealt with this issue twice already.
Open the passenger door, and pull out the "accordion" rubber tube that houses the wiring going into the door. After you do, pull the wiring out of the body side until you can see the main plug/disconnect for the door. You will *most likely* find that one of the wires has a clear plastic sleaving on it, and it has slid down the wire a bit, exposing it. When this wire is moved, it contacts some of the metal in the dash, and shorts/grounds/whatever. Take this wire and wrap it with some electrical tape to keep the wires covered when it goes back in the dash.
This was my initial problem, that compounded much worse to cause almost all of the electronics on the vehicle to go haywire.
Hope that helps!
Jon