Power Seat Switch Cleaning
 

(I'm re-posting this, as it appears the original got wiped out in the Sept server crash. It's not as complete as the original post, but I think better than nothing)
I'll assume you've tried the contact cleaner sprayed into the switch on the car fix and it either didn't help, or was short-lived.

Firstly, here's a good reference with pictures on doing this job on the same switch that is used in the Range Rover. http://www.rangerovers.net/repairdetails/seatcontrols.htm The idea is to disassemble the switch, clean the contacts, and re-assemble, so without going into detail on removing the switch fron the door (which varies according to model/year), here are some pointers. (All work was done on my 1985 380SE passenger side switch BTW)

- All work is easier if the lower half of the switch case is kept level and steady, so start by screwing the switch case to a piece of wood. You can use the 2 mounting screws, or shorter sheet metal screws.

- I borrowed the wife's cookie baking pan, which is large, flat, (the pan that is) and has raised edges to catch stray parts. I also lined the bottom with paper towel to make it easier to see things, prevent them bouncing.

- Work the little plastic clips around the circumference by inserting small 'wedges to keep the sides of the lower case half out a bit from the clips. I used small flat blade screwdrivers and bits. There were 7 clips on mine. I found that when the clips/pins on 2 adjacent sides are pryed apart, the cover comes right out, straight up. When it did, all the little balls were still sitting on their posts.

Note: First time, it's nice to have everything stay together when the cover comes off (pic 2 was shot right after the cover was removed), but I'd just dive in now and put it all back together later. It's a very simple mechanism. The little wing shaped contact bars are pushed down on the lower contact spots, which look like old-time ignition points, when the spring-loaded balls are squeezed down by the shape of the lower and upper case halves. The corrosion that covers the contacts and the bars prevents current flow and that is why your switch fails. The fix is to remove the bars and clean them and the points.

- All but the main moving piece can be removed and the little bars cleaned with fine paper, say 600 grit, with or without spray contact cleaner, same for the contact points on the lower case half. You can also swap the bars around to move a high-use pair to a lesser used part (like the headrest pair to the main).

- Re-assembly is just as easy. Simply reinsert the bars and replace the springs and top balls (and any lower balls that you might have dropped if you inverted the lower case). This is where that piece of wood does its stuff, keeping the assembly steady so none of the balls fall off as you carefully reinsert the case cover and engage those tabs.

This is an easy and satisfying job BTW, and anyone with a reasonably steady hand can do it. :)

Cleaning the driver's side switch with memory buttons
 

Today I decided to clean up my driver side switch, and took the opportunity to sharpen my close-up picture skills. This switch is the same as the passenger side except for the 3 memory buttons. I'll add a few notes to the previous post to complete the procedure.

- It is possible to remove the switch from the door without removing the panel, at least on the W126, but it's safer to remove the entire escutcheon plate around the door handle, and the upper screw for the armrest, first. This will minimize chances of breaking plastic tabs getting it out.

- Notice the picture of the case with the screwdrivers and bits stuck around the tabs to keep them pryed out for easy removal of the cover. By using gentle pressure, the cover comes out smoothly with no damage to the tabs or case body (you know how this works if you've taken apart a Hirschmann antenna case, similar design).

- Cleaning the little contact bar 'wings' is easiest with fine steel wool. Just a quick buff will polish them clean.

- A square shaped blade in an X-Acto knife works really well to do the contact points on the case bottom. Just scrape until they are clean and shiny.

- When reassembling, put a dab of grease on the tops of the springs to hold the balls in place. Put a dab on the posts on the back of each of the 3 memory buttons to hold their little springs on too. Also, a piece of masking tape on the buttons on the outer part will keep them from dropping out when the cover is placed onto the case.

After cleaniing the contact points, why not take a Q-tip and place a dab of dielectric (sp) grease, such as is used on light bulb contact points, on the now-clean switch contacts? This should extend the length of life of this job. Just a thought.

After cleaning the contact points, why not take a Q-tip and place a dab of dielectric (sp) grease, such as is used on light bulb contact points, on the now-clean switch contacts? This should extend the length of life of this job. Just a thought.

I had read that others felt grease, of whatever type, tends to hold dirt and that was a valid argument to not using any on the slides. I'm not really convinced one way or the other, and tend to agree with you. I'm not sure of why others say the clean-up job only lasts a few years either.

Excellent post !
I just did this today, used 600 grit to clean contacts and
electrical cleaner to get out the gunk.
Also had to repair broken post on switch.
Used piano wire, carbon fiber tube, and epoxy to create new posts for switch.

New switch $140.00
 

After I did this I found your pictures and info. Wish I had seen it first. A little disturbing when opened upside down and 17 bebes and 9 springs fall out. New to the forum and love it. Thanks to all. 87 300SDL driver side seat recline clicking now but still not moving any help?

thanks for posting this!!! i was able to clean the switch following your pic's and everything works correctly now

Thanks for this post! It worked! Takes a little patience, especially removing the cover, but well worth the time and effort.

When I owned my Range Rover, I used these steps to clean those switches, about to do the same in my 126.

Nicely done article, unfortunately I lost 3 springs in the process...somewhere in my garage...:eek:

Oh well...