What is the most likely cause of non functioning tach on a '80 300SD. Is it an electric or mechanical drive?
Does the dash remove the same as the W126?
What is the most likely problem with the tach?
Is there much diference between the W116 and the W126?

thanks

the problem is a lot easier to fix than it seems. check out

http://www.mbz.org/articles/electronics/300sd_tach_amp.html

And the engines in the W116 and W126 300SD are basically the same but W116 had 115hp I beleive.