john deere tachometer

[chris5280]

have a jd 2155 that the tach dose not work all other gauges work on it and have power to plug works with multimeter on plug new tach

 

[Alec_t]

Welcome to EP!

and have power to plug works with multimeter on plug new tach

That's not making sense. Please explain.

 

[Bluejets]

have a jd 2155 that the tach dose not work all other gauges work on it and have power to plug works with multimeter on plug new tach

Apparently they have a gear tooth sensor on the front of the timing cover with a one wire pickup.
So I imagine the sensor to be a high resistance coil to ground.