Tach problem

[el cazador]

I recently rescued a 1999 1200 that has tach that does not indicate. The speedometer and odometer did not work until I replaced the vss. What tests should I do to troubleshoot my tach?
El Cazador

 

[rancid]

get a wiring diagram check power and signal inputs aswell as ground, thats a start.

 

[3737pisces]

My Tach sits 10 up from 0 even when turned Off..Thats with the ignition turned Off. What can the trouble be? I turn key on then off then it sits on 0.

 

[glider]

My Tach sits 10 up from 0 even when turned Off..Thats with the ignition turned Off. What can the trouble be? I turn key on then off then it sits on 0.

How does it read with ignition ON? I have seem some tachs that do that but are accurate when running.