I would do a search on power seats and diode.

You probably have a bad diode

The diode in my 87 300d is in the rear of the fuse box encased in a gray little box.

It pushes into the fuse box behind all the relays. You may have to remove the combination relay to get it out.

Pull it off. Pry it open Note the direction or orientation of the diode. use a soldering gun to remove and replace the diode.

The part number is on one of the earlier posts you can get it at radio shack for about 2 bucks.

THat could be it.



good luck

bob c