Rev counter out of control

[Hans]

My rev counter of my xantia TD'94 reacts on all electrical changes of the car (like disco).
eg if I put my fan to max, the rev meter goes to max.. any ideas? I cleaned the battery connections but did not help.

[Kowalski]

Check your earth points, its most probably that one of these is slightly dodgy, either that or your alternator / battery are putting strange voltages into your wiring.
My Xantitia Speedo sometimes dips a bit when the wipers are on intermittent, each time the wipers start, its probably the same sort of thing.