I suspect your problem may be the seat adjustment control relay. It is located under the panel that is forward of the spare tire cover. It should be Part #: 002-542-22-19. Check your messages for more info. I sent you an email also.
It seems that I can no longer attach files to messages or emails created on the forum. It's possible that I was never able to, my memory is not what is used to be!

Any way, back to your question, the wire colors in the harness are white/blue and black/blue, positions 11 and 12 in the connector. The wire colors on the wires attached to the three motors under the seat are all black and white.

Robert

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Mercedes Benz Master Tech - Retired