2005 tach wiring ?'s

[scotts]

Lights work.
The harness for warning system is fine.
Tachometer does not move....I have the a yellow wire hooked up to the brass post that says rev on the case. The ground for the lights is connected... do I need another ground? I tried putting power on the other post. What am I missing? Is there a way to test these gauges?

[scotts]

Test

If you run a magnet over the gauge and it does not move your gauge needs to be replaced. No need to chase wiring.