Yes, the window goes up but not down. I can make it go down only when I connect battery power directly to the motor.

This is a convertible. There is no rear door and no point where the wiring would flex.

I have the schematic. It appears to me that to operate the window, the two wires going to the unit are the power feed and ground. These two are the electrically reversed when going the other way.

All windows are operated through the convenience control module. There are eight relays - two for each window - one up and one down. The down relay for the rear window operates when activated. It doesn't appear burned. If anything, it's the front window relays that look kind of burned. The convenience control module does have some light corrosion on it. I hate to spend $600 just on a hunch and see if this is the problem.

There is an added complexity to my system. The windows are also controlled by the power top system. But I don't think it operates in series with the other wiring.