tach

[chev0545 231]

put a new tach gauge on a 520 the needle won't move.i have pink & grey on top poles double black on bottom pole.

[gwest_ca-(File Mod) 10,478]

Pink powers the gauge - 12 volt

Grey goes to one of the AC terminals on the voltage regulator. (I believe it will only work on one of them.)

Black is ground.

[Handy Don 10,552]

30 minutes ago, gwest_ca said:

(I believe it will only work on one of them.)

 

Pretty sure the stock wiring brings the sensor (gray) wire through the 9-pin connector direct from the engine to the tach.

 

As noted by @gwest_ca, Pink powers the electronics inside the gauge (via the Accessory terminal on the ignition switch) and Black is ground.

[chev0545 231]

39 minutes ago, gwest_ca said:

Pink powers the gauge - 12 volt

Grey goes to one of the AC terminals on the voltage regulator. (I believe it will only work on one of them.)

Black is ground.

what's the ac terminals

[Handy Don 10,552]

Just now, chev0545 said:

what's the ac terminals

AC comes from the stator via the two wires going to the outer terminals of the voltage regulator. Depending on the VR, one of the outer terminals may be grounded within the VR and only the other one will register AC current.

[chev0545 231]

this is a new gauge.i still can't get it to work.i move the grey wire on the post the needle will move some.

[lynnmor 6,762]

Check the voltage at the battery with the engine running it should be greater than 13 volts.  Make sure that the voltage regulator is properly grounded, the mounting bolt is the ground.