E 400 power drivers seatwith a mind of it's own

[Barkingbenz]

I had this problem on a 90 E300 and now on a 92 E400. The seat switch sometimes does not activate the seat, but sometimes it feels and Sounds, like a pinball machine under the seat cusion, or will start making it's own adjustments at will. Don't think it's the 2 program seat switch. Even with key off it taps away.
Is it just relays and how big a deal [$ and time] is it?
Joe