Cleaning the righthand mirror switch DIY

[Jeremy5848]

This DIY was done with the switch from my 1985 W123 300DT but I suspect Mercedes used the same switch for many moons. The switch is a Hella product (201 820 06 10) and very well made. The parts count is high, at least 17 bits and pieces by my count -- I'm surprised Phil can afford to sell them for $23.50.

After getting the "shift lever cover" or "console" loose (but that's another thread), I removed the switch (it's held in the cover by two spring clips) and took it over to my bench, where I laid out a soft mat to keep little parts from bouncing all over. This is one disassembly job you want to do with attention!

Fortunately, almost everything is keyed so it can't go together backwards. The wire socket is keyed to the pins on the back of the switch, the switch is keyed to the console, and the back of the switch assembly (mine is yellow plastic, five pins plus key) is keyed to the body.

To remove the back of the switch, insert a couple of small screwdrivers and carefully spread the body of the switch so that the four little locking tabs come out of their holes. Gently lever the back out of the body and, with the operating lever down, lift the back out, noting the keys that allow the back to go in only one way.

Inside the body of the switch is a zoo of tiny parts: seven springs, three "dumbbell" contacts, and a plastic pin. Don't lose any of them! The square white plastic part that holds six springs and the dumbbells is NOT keyed so note how it goes into the body. See my pictures and take notes.

Carefully remove the dumbbells and the six springs to a safe place. These pieces are now ready to be cleaned.

The bottom of the operating lever is drilled out for the seventh spring and a plastic pin. This seventh spring is longer than the other six. You may need to use a paper clip to get the spring out. Put the springs someplace where they won't get knocked onto the floor. I threaded all seven springs on the paper clip and didn't take them off until I was ready to reassemble (see the "After" picture).

I couldn't figure out how to remove the operating lever from the body of the switch so I just left them together.

With the switch in pieces, I photographed everything and put all the pieces in a small ultrasonic cleaner with water and some dish soap. A toothbrush would probably work too. After an hour, I rinsed all the pieces -- like new! I polished the copper circuits on the bottom piece with "Twinkle" copper cleaner and buffed the dumbbells with a bit of 0000 steel wool. Next, I put the spring and pin back into the operating lever and laid the body of the switch upside down on my pad.

Since I didn't notice until then that the white square plastic piece was not keyed, I had to go back to my pictures -- thank goodness I had them! -- to see how it went back together. See the picture with the red arrow labeled "KEY." That key is for putting the switch back into the console, but it serves to show you how the white piece and its springs and dumbbells MUST go back into the body of the switch. The fourth set of holes has nothing in it.

Once all that is together, the only thing left is to pick up the back of the switch and, orienting it so that its two tabs fit the correct slots in the body, slide it back into the switch (making sure the operating lever is centered and none of the dumbbells have fallen off) and press it down until the four pins lock. You're done.

Be sure to test the switch in the car before reassembling the cover. You can power up the car with all the other switches removed.

Jeremy

[toomany MBZ]

VERY good cleaning job!

[Stevo]

Good job, I'll file that away for future reference. My 85 240 has that switch which still works, at least for now

[Yak]

I cleaned my switch this weekend.

Two things to add:

The white center shaft is a friction fit with the exterior black knob and can be "gently" pulled apart to facilitate cleaning the crud out of the bowl-shaped carrier.

The white square carrier piece is "sort-of" keyed. It can only go in two ways, with a 180 degree rotation due to tabs or cutouts on the sides of the square. Look straight above the red arrow in the picture and you'll see an asymmetric bump that fits into a hard-to-see groove on the black external piece. The "sort of" effect comes from the obvious wear marks on the copper circuit board. Since that piece is keyed ("large tab into large slot, small tab into small slot") it's straightforward to deduce where to place the dumbbells.

I also cleaned my other switches. The rear window switches wouldn't work due to the "safety switch" in the center of the driver's side not sending current to the rear switches. They worked from the center console, but not the rear switches. A little cleaning and all the switches are not working.