okay i have post many many topics here so far,. surprized at how many knowledgable people there are here. great forum!!anyways i ask about the alda on previous post and does look tempting. but i heard 1 in 10 would go bad. so i think i will wait till i have a spare on me before i do that. and one more questions my alda thing does not have a black top to chop up. the knub up there is just metal.. like 1 casted piece.. is that weird?

anyways now to this question. i think my tach is bad. i am not talking about bad connections or anything. the tach is self is bad.. so i was thinkning of an aftermarket tach. now if i buy one of those can i splice the wires that goes into the .. uhh. black screwy thing on the drivers side (i have no idea what these parts are) has anybody try this yet? i am in the process of resotring this 1979 300sd.. every thing but the engine is bad.. fortunately the engine is running strong!!! MB rules!!!

I hate to see you cut into your wiring harness like that. It really can ruin a car and make it that much less original.

I have a few instrument clusters, and I think I have when with the tach/clock unit. If I do have one it is for a 300D. If someone can tell us it is the same as the early SD, I will sell it to you reasonable.

If the problem is that it is not working, it could be the sensor and associated wiring rather than the tach unit itself. Maybe someone else reading this is familiar with the troubleshooting of the tachometer system. Also maybe they can tell us if the tach/clock is the same.

Have a great day,

thxs for your concern.. i will try to take it apart and try to figure it out. once more. might be a loose connection. and i about the gauge cluter , i'm pretty sure mine is not a sd cluster either.. it is not even a D cluster. i bought it as a part some where and it works..

check search for cigarette butt trick the tach on my SD is working fine after a year with butt trick , aftermarket tachs ain't to bad on GTO's......
William Rogers.....

You have a '79 SD but the instrument cluster is not a SD cluster? What instrument panel does your SD have? Before you stick some Pep Boys special tach. into a Benz try the cigarette butt trick.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member