Digi speedo flashes - 412 Sprinter

[motovelo]

Anybody got any clues as to why the speedo flashes on my van? It only does it the moment I engage any gear and move but stops when in neutral?? I believe it's a warning of some sort but have no idea. The van was a four tonner but has been downgraded to a 3.5 by having bump stops fitted on the rear axle and as such still has a tacho fitted and I'm wondering if this is something to do with it?

 

[daz 585]

narr moto, it could be a faulty sender unit on the gearbox? you could always change the tacho to the 312 set up with no tacho now its down rated,, or could be a wire from the sender unit up to the head??, if you realy want i can tell you how to un plug the milage completly so it stays blank?? takes around half hour or so to do it,