Hello
Easy check as far i remeber.
Let the engine run and rev it over 2500/min.
Hold the throttle from the enginbay at that rev. Use your left hand and press the switch while the engine is still at over 2500/mn.
Now the enginerev should drop to 800 - 1000 for a sec and then speed up automatically to 1600 - 2000 and fall back again. It will always cycle beetween those marks even if you have full throttle then. ( Don´t try it with more then you need.
If it will not work the system has a failure.
First would be to short the switch just by connecting the spades. And then look if you have power on the selenoid.
Very easy to track down to the tachometer unit.
The microswitch is a Klöckner ( brown bakelit ) or Wherle ( black ) unit and was used at Mercedes Benz MFI too.
Mostly Bosch dealers stock them too.
They have very rarly failures. Mostly if the rubberboot is missing or craked.
If everything brakes you can adopt the 911/964 convertible top switches. Make sure the amperage will suit up.
Grüsse
|