The tach in my truck has recently been buggering up on me. Whenever I turn my truck to the "ON" position, the tach shoots right up to about 3500 rpms, and it stays like that the whole time I am driving. When I turn the truck off, it goes back down to 0. Do any of you know what could be causing this?

I know its not the biggest deal, but it drives me crazy, whats the point of having a tach that doesn't work?

 

Short in the wire perhaps?

 

Could be. Ill strip it down tomorrow and see. Hopefully thats all it is.

 

Couldn't find any shorts throughout the wiring. Does anyone know what else could be causing this?

 

Does anyone know if it could be a fuse causing this problem? If so, which one?