2E engine tachometer install

There should be an external plugin on the distributor that you can use to power the Tach .
If I remember correctly you should have three wires on the Tach itself . A ground wire , A power wire for the Tach light , And a wire that attaches to the distributor .
The Tach should have come with a wiring diagram !
If not try the any of two wires to get the Tach to light up , after you find thoes two , the last wire will connect to the distributor.
Hope this helps .