Passenger Rear Window Motor Weirdness

My 2005 Gen 2 w/506k stopped letting me raise or lower the RR window (either switch). Over the last few months, it only worked from the Driver's control, but now that doesn't work. All the other windows work fine from their own controls or the Driver's.

It seems to have power to the motor, and I hear a faint relay click from the vicinity of the motor when I try to activate it (either from the front or the rear switch), but the window stays all the way down. I borrowed the LR door switch, but that didn't make a difference.

Finally, I took the motor and window scissor assembly out (not fun, when it's all the way down), and secured the window all the way up with tape and little bungees, so that I could drive on the freeway, later on.

Then, when I removed the motor from the scissor assembly and plugged it back into its harness, the motor started turning constantly when no window control button was pushed -- but only in one direction. The driver's control of that window made no difference to the motor turning in one direction. But if I rock the rear window control in one direction, the motor stops. Rocking the rear switch the other way does nothing (motor keeps turning).

Has anyone else had this adventure? Is it likely the motor, or maybe some component in the master switch?
One thing I have not yet tried is manually feeding the motor 12v from wires, and switching them to see if the motor will then reverse.

And just curiously, is the motor supposed to always run? Does it "normally" stop when the window hits full up or full down, via some sort of feedback relay?

Inquiring minds would like to know.

 

Great details in the reply!
I just picked up a new/used Driver's door master switch to test. I will also just test polarity of the voltage coming TO the rear switch when no rear switch is attached at all, as well as when it is attached. If it's correct, then I will blame the motor, and find a new one...
Really appreciate the wiring diagram w/wire legends. This will speed diagnostics up for me.
I'm still pretending that the car can go another 500k...

 

OK, the driver's side switch was the culprit.
I got one from a wrecking yard for $20, and it corrected the problem.

• The motor no longer runs when the button is NOT activated.
• The window goes up and down as expected.

So the main switch had some sort of fault that was always sending power to the motor.
On the bright side, I now know how to take the window actuator assembly out of the door with minimal curses, should it ever happen again.

Thanks for the insights, I'll shoot for more miles on this beast!