My turn signal/multifunction switch does not lock down when activated. I've read threads here about a simple fix that involves filing a new notch that allows it to lock in place. One of those threads had pictures, but they don't show up anymore. I've had the switch out of the column a few times, but can't figure out exactly where to file these notches, even after studying the operation of the switch. It seems really smooth, like it was never meant to lock down in the first place. Can anyone advise me? I've attached a few pictures.

Attached Thumbnails

   

__________________
1976 240D "Katja"

i have the same problem. every once in a while it will lock down when turning left, but that is rare. I would like to fix mine as well, so I too would appreciate any help on this issue.

Refer to signal2.jpg.

Notice as you move the lever that a spring loaded bump or roller or whatever, moves along the stair stepped openings. The stairs are the detent. You need to use a small dremel bit and make a drepression for the roller to drop into when the lever is at it's end of travel.

Take your time, be gentle or you will go too deep and ruin the self canceling. I actually chucked my dremel bit up in a small battery drill so it wouldn't go too fast.

You could also try a needle file but I'm not sure there is room.

Be sure to disconnect the battery and figure out a way to get the filings cleaned out. I may have used a shop vac and a WD40 rinse.

Michael

__________________
Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

Hello,

Yes as Michael suggests, a little at a time or the unit will stick on if you make the notch too deep. I like using a dremel also, but a small round needle file will work with a lot more work. You can just unfasten the switch and wok on it or unplug it and remove it from the car. The large plug on the end, which is up under the dash, will fit through the small opening in the steering column housing.

I flush the metal filings out of the unit with compressed air and/or electrical contact cleaner.

Notice the unit has a tab sticking out on back. A cog on the steering shaft hits the cog as it rotates and cancels the switch. You can test its function by pushing the tab in both directions.

__________________
Joe Alexander
Blacklick, Ohio
1964 220SE Rally (La Carrera Panamericana someday)
1966 Unimog 404s (Swedish Army)
1969 300SEL 6.3 (sold)
1969 280SL Pagoda
1973 280SEL 4.5
1974 450SLC FIA Rally car (standard trans)
1982 300D turbo (winter driver)
1986 560SEC
1989 Unimog FLU419 (US Army)
1991 300TE (wife)
2002 SLK 32 AMG (350 hp)

I just repaired my '76 240D W15. I'll walk you through what I did in case someone out there needs this info.

First, work the boot off the shifter arm. Pretty easy, I didn't even need tools. Should slide right off, get it out of your way.

There are two screws holding on the main body of the shifter mechanism, Phillips. Remove these and set aside.

Two small screws at the back secure the horn wires and need to be loosened. Mine were difficult, the screws seemed soft. I was able by pressing very hard and using a good bit, but alternatively the wires could be cut and re-spliced, but not recommended if possible.

Once you have the unit out on the bench, how and where to make said notches. Well, if you move the lever up and down you can see the little roller guys that roll up to the center. Where they stop, a small notch needs to be created so they have a home to pop into. VERY SLIGHT notch is only required. I made one perfect, and one just a bit too much, makes it hard to pop out manually if the auto-release isn't needed (example, you are changing lanes and have to manually return to neutral)

Spring can be removed but not necessary. If you take the spring off, there are two rollers that can easily get lost-so don't lose them.

Ok, I had a dremel kit but it didn't have a tool that could make the correct size notch, which would be about the same size as the roller. I bought a needle file kit at Harbor Freight for a couple dollars. One of the files is round. Just cut that baby off as needed so when you chuck it in an electric drill the thing spins without wobble. Then go at it. To clean up my mess I used contact cleaner. Then re-oiled with a very light oil, I used LPS-1. Finally I put in a smudge of grease in my new notches.

Hope this link works for pictures. Click on each for a description.

https://photos.google.com/share/AF1QipPuY9CQ9OGei2Qp8tPlJ9sI3_uCKV53ZD8jXqH8zHmSjLCuAohKCQN81G5GP475jA?key=YXJyLUFPNFdJM21YenliZmVlV 2xQR1RJUF9RTW9n