Hi, checked the OVP fuse ok,
found the tacho sender has 1 wire attached?
Is there a way to test it or do i just remove it find the part number, order from MB dealer and replace?

The tach sender has 2 wires inside. There is a 2-pole connector behind the battery, near the OVP relay. Find this, and separate the connector. Connect a voltmeter to the leads from the sender (engine side), and start the engine. There should be an AC voltage present which increases with RPM. Something like 5V or so... it's not a lot. Make sure your meter is set to AC, or it will read zero. If there's no AC voltage, the sender is bad. If the AC voltage goes up & down with RPM, clean the contacts, plug it back in, and check the tach. If it's still dead, you may need a new tach/clock cluster.

:lipsrseal

Hi Dave
fanx for your great help,
i reckon i have found the 2 pole connector you mention when i checked to OVP, the 2 pole connector had corrosion on it and had been taped up.

Will test it as you advised.

The tacho sender? the thingy i thought it was (photo) seems to only have one wire.

Have i got the right bit?

Photos are fabulous - saves lots of typing. That is the oil pressure sender. The tach sender is close to that, but below it, and fastened to the bellhousing with a single Allen-head screw. Here's a photo of the tach sender, with the long attached cable:

http://img.eautopartscatalog.com/live/P401338301BER.JPG

Hi again Dave,
the pic was invaluable, checked voltage 2 - 6.5 Vac.

do you know how the Klima gets the tacho input, ie the voltage goes to the tac to th erg to the klima? voltgae goes to the Klima to the tac?

The essence of the question is does the tac (instrument) need to actually work for the ac or the input for the tac.

I dont doubt i will be sure to fix the tac instrument to keep my ride sweet but th ac is my no 1 concern.

looking for my next step.