Any ideas how to discover the fault in my tach!!! My cruise wont work either. Dont even know where to start.

Hard for anyone to give you input with this little information.

__________________
Der Panzermann und Fraulein Fahrvergnuegen

1991 420SEL 201K "The Big Blue One"
1985 300DT 205K chassis/285K engine nee California emissions "Goldbug"
1983 300TDT 255K "The Womble"
1983 300 DT 214K "Sea Sprite"-Rear-ended a truck
1983 300SD 285K "The Donor" Gave his life so that others can live
1980 500SL Euro 105K "Der Panzer"

You start by using the search function. Then come back with more specific questions.
Lots of info when you search.....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

here, use this link. it will show you how to fix your tach. i had the same problem, and i did it. it works. http://schumanautomotive.com/forums/showthread.php?t=1842
as for the cruise control.. good luck. thats a whole other ball game

__________________
1983 mercedes benz 300D turbo diesel.
pyrometer, boost/vacuum gauge
exhaust dump pipe
turbo- 15 psi boost. 25 psi capability
disconnected EGR

A non functioning tach is usually caused by the rpm sensor on the driver's wheel well. It can be tinkered with to get more life out of it if you follow the link above.

The cruise control could be the cruise amp which is under the dash on the driver's side. It's a silver box. Resoldering all the connections will sometimes fix the problem.

__________________

Again, better description of the problems would aid the analysis....

__________________
Der Panzermann und Fraulein Fahrvergnuegen

1991 420SEL 201K "The Big Blue One"
1985 300DT 205K chassis/285K engine nee California emissions "Goldbug"
1983 300TDT 255K "The Womble"
1983 300 DT 214K "Sea Sprite"-Rear-ended a truck
1983 300SD 285K "The Donor" Gave his life so that others can live
1980 500SL Euro 105K "Der Panzer"