W124 odd instrument cluster failure

[bluevenetian]

Yesterday a few of the instruments readings on my W124 stopped working. Fuel, oil pressure, temperature - all kaput But, the speedo still works, as does the odometer. The rev counter is also bust, but the clock is still keeping excellent time.....Any ideas on cause and fix?

 

[BillyW124]

To save problem solving, it would be far easier and quicker to replace the 2 units that houses the kaput instruments.

Get a donor cluster from the scrap and swap the unit that holds the kaput gauges, the rev counter and clock if all other investigations fail. Easy peasy job.

I can't remember if there is a fuse behind the cluster... but usually if more than one thing goes at one time usually means somthing along those lines.

Maybe earthing is another possibility.

Your speedo will work as its mechanical

 

[hotrodder]

As said speedo and odometer are mechanical.

I can't remember if there is a fuse behind the cluster...

There is, for the instrument lights. Don't think it covers anything else/has any friends

Check the fusebox* first, the clock is on a different fuse (#9?) to the rest of the gauges. IIRC the fuse you want to pay most attention to is #5 as that covers (amongst other things) the instrument cluster and tacho. Some of the other things it covers may not be fitted (cruise for example) or not obvious (bulb out warning). The lid should be labelled so pay more attention to what it says each fuse covers than me

* A cursory glance at the fuse won't necessarily cut it in that they can suffer tiny cracks and/or corrosion as well blowing in an obvious way

 

[carat 3.6]

Mine had a fault in the light control unit, when you put the brake lights on, it would short out and knock all the gauges out.

See here: http://www.mbclub.co.uk/forums/electronics/115942-1995-e300-diesel-electrical-sillyness.html

 

[bluevenetian]

Thanks all, I checked the fuse - it looked ok, but replaced it anyway and hey presto! all working again