dodgy rev counter

hi
can anyone tell me why my rev counter needle has started jumping around.
only seems to happen above 2000rpm when cruising at speed. the the needle keeps dipping and rising at random. noticed as well that when you do the windows up it dips then rises when you take your finger off the button.
its a 300 tdi btw.

Check the connection of the small wire on the back of the alternator as thats where the rev counter gets its feed from

I noticed mine doing that a few weeks ago but hasnt done since, I'll check the alternator conection now. Thanks.

Nice one! That's exactly what the problem was.
Cheers

no problem

My rev counter started doing exactly the same a couple of weeks before the alty packed in . Just a heads up

Could also be CPS (crank position sensor ).