I wrote a description of disassembling, cleaning and reassembling a driver's door seat position switch for my 1987 300E to a friend. I thought I would share my narrative with the group:
I tackled taking a Mercedes driver's door electric seat position switch apart to clean the contacts. I bought it at the Big Three Automotive Swap Meet in San Diego last year for $2.00. They are $125 or so new.
I have taken the simpler 4 switch passenger one apart and cleaned the contacts. The driver door one I took on yesterday has the same forward and backwards and up and down for the seat bottom, forward and backward tilt for the seat back, up and down for the head rest, but also has a number 1 and number 2 memory buttons with a third memory position setting button.
The two part case prys apart using a thin screwdriver to loosen the snap paws and there are 17 little ball bearings, 9 tiny springs, 9 brass rockers with 36 electrical contact pads that must have the corrosion polished off of them. I put it in a box to pry it apart so any ball bearings and springs don't fly across the room.
The memory system has three brass pressure contacts that I could slip a strip of 600 sandpaper into to clean the corrosion from both sides of the contact. Only one plastic housing cover snaps all three into place.
After polishing all the corrosion off the electrical contact pads, the open V shaped brass contacts with the electrical pad contacts on either end are then set into the housing above the electrical contacts pads in the lower casing, a ball bearing is set into each brass V center, then each of the 5 plastic rocking switches are set on its brass pivot shaft into the shaft holders in the lower plastic base housing above each brass V contact plate. Then a tiny spring is put down into the two holes on either side of the plastic rocker switches to rest on top of the ball bearing at the bottom in the center of the brass V and a second ball bearing carefully balanced on top of each spring. The top cover can be used to determine which way each rocking switch should go so its shaft is centered in the hole in the top cover. The top cover is carefully lowered down so each of the stems of the five rocker switches goes through its hole without jigging and knocking one of the ball bearings off its spring. The top cover pushes the ball bearings down on their springs and secures them tightly in place when the top cover is snapped back down to the lower plastic housing.
Gotta be a frugal Scot to tackle rebuilding one of these switches. Kind of satisfying when accomplished, though.
Pete Macintosh Cowper (1987 300E)