Tach question

[badams270]

I am wondering if there should be a hot wire to the tach? With the key on I checked the terminals and there was no power to either. Does the motor need to be running to get power to it?

 

[hkeiner]

Re: Tach question

This Teleflex site contains a link to troubleshooting all sorts of gauges including a tach. The link to the tach troubleshooting also shows a typical wiring diagram for a tach gauge. It should be helpful to you.
http://ww2.tflx.com/tech.html

In short, a typical tach has three connections.

-Ground (wire connected to system ground)
-IGN (12v wire usually comes from ignition key switch)
-SEND (usually a gray wire from the voltage regulator on motor)

There may be a fourth connection for a panel light. Also note that the Teleflex tach wiring diagram has a mistake on it. It shows the 12v wire from switch going to the SEND post and the tach wire from motor going to the IGN post. It is the reverse of this. Shame on Teleflex for making such a mistake on what is an otherwise excellent resource.