Driver side power window motor replacement

[Poorboy]

My 98 ML320's window went down and cannot get it back up.
I pulled the motor out and tried it without window. When I click
"down", motor will run. (and the meter will read +12 V coming).
When I click "up", motor will not run, and the meter will read -12 V.
I think the motor is partially bad, not the regulator, which is the
part connect motor to the window.
Any one with experience or knowledge, please comment.
Thanks.

[eric242340]

Are you sure it is not a faulty window switch? Try swap the connector from drivers door switch to passengers door switch to see if it is the switch.

[Poorboy]

Mr. Eric:
Thank you for pointing that out to me. And you sounded like you are responding from accross the ocean - Hanchow, that a city in China famouse for it's beauty!!
I used to have a Ford Aerostar, with same problem, and by changing the
motor made it work for a few more years. So my mind was programmed to
think like that. Thank you again.
By the way, I understand that our great great grand father moved to Taiwan
from (not Fuchow) Chenchow, should be not too far from Hanchow. Bye