sunroof motor

[recorderguy2001]

Hi all,
Great site! I've search around for info about 123 sunroof problems, and I haven't seen any quite like mine. Perhaps someone can help. I recently aquired an '83 240d. The previous owner told me the sunroof didn't work. With warmer weather approaching I thought I'd see if I could fix it. I checked to see if the motor is getting power and it gets both +12V (rockerswitch down) and -12V (rockerswitch up). I then tried to open the roof manually to see if the cable is intact. It opened up but required more effort than I think it should. Just for giggles I tried the switch again and I heard the motor turn a little before it stopped. At this point I thought that the whole works might just be a bit gummed up, so I opened and shut the roof manually a few times and tried again. This time the roof closed (slowly) under it's own power. But here's the rub, I can't hear the motor even trying to open the roof. I double checked to make certain that the power is flowing with the switch either way (+12 and -12). Is there any reason for the motor to only work in one direction? Beside the obvious cleaning, checking for broken parts detailed elsewhere, where should I go from here?

Thanks,
Peter