I have been having some problems with my 116.120 since putting it back on the road after a number of years (6) in a climate controlled storage facility. The biggest problem I had when I put it back on the road was no turn signals, fog lamps or hazard flashers. Everything looked good, fuses, grounds and even the flashers, but something was very, very wrong.

After looking at every possible scenario, we discovered a mysterious flasher-like unit, next to the steering column, hidden behind the knee bolster. It has (3) round pins exiting the side of the black plastic case and it bears Bosch Part Number 0 335 200 007.

When I replaced this unit, everything started working. However, so far, not even MBZ can tell me what this unit is. Based on the number of diodes and resistors I found inside it, I would surmize that it is some type of voltage regulator.

They are easy to find at your local Pik-N-Pull Dismantler and can be had for $1.00.

Now, I only have a few more electrical demons to sort out...

One of them is crazy, intermittant tachometer fluctuation. Sometimes, the tach will just go wild, swing all the way to 6,000 and back to zero. Sometimes, it will just swing to 6,000 and stay there until I turn the key off.

It also 'bounces' when the turn signals are activated. All of the ground connections have been checked and the large ground grom the engine to the body is new.

Interestingly enough, when the tach starts its little dance, I can hear something in the passengers footwell make a clicking sound that is consistent with the needle movement.

I wonder if the transmission overload protection controller could have something to do with this???

I replaced the sending unit for the temperature indicator and it still reads just a shade above 100°F even after extended periods of driving. I find this odd since I went against my own teachings and installed a new Mahle 80°C Thermostat, which I verified is functioning.

The engine is hot to the touch, but apears to be operating within a normal range of temperature.

The fuel indicator will 'bounce' from time to time and will sometimes drop to absolute zero and stay there until the key is turned off.

I have new, replacement indicators that I can use for testing, but I think the problem lies elsewhere.

Anyone ever experience this malady before???

Your input would be greatly appreciated...Bert

I will send a crisp new $1.00 bill to anyone who can correctly identify this 'flasher' unit... ...Bert

Sorry to dig this thread up from the dead, but I thought that someone who may need this information in the future might find it worthwhile.

I had this same box fail on my W116 last week. The Bosch part number is, again, 0 335 200 007. I also have a Mercedes part number; the p/n is A 001 544 97 32, and M-B describes the box as a "Blinker Unit". Best I can tell, neither Fastlane nor any other aftermarket parts sources carry this box, but it is available from the dealer. I bought mine from a dealer for $50 (this was with a discount, though, since I know someone who works there...retail was closer to $90). I would have tried a junkyard, but I did not have the time to scour through a series of yards that almost never has any 116 chassis cars, so I opted to just buy the thing new.

Best I can tell, this box handles the flasher function (much like the black flasher box forward of the gearshift lever on the later 123 chassis does), which is interesting since I also thought that the 4-way hazard switch also contained the flasher. BTW, I also disassembled the hazard switch, and all it is is a series of connectors.

Again, I just thought this information would be of use to someone. Take care...

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

I revived this old thread as this problem seems to have re-appeared in my W116 after a long absence.....Ideas anyone????

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

My 1979 300SD used to have turn signal, flasher, and tachometer problems. I pulled the instrument cluster out to find some of the wire connections for the bulbs broken. The broken wires would short out on other things. Sometimes when I used the turn signal it would make the tachometer jump around. The bulb wire connections behind the dash cluster are very fragile and can fatigue. Maybe try inspecting behind your instrument cluster if you haven't already.