DIY: TACH INSTALLATION INSTRUCTIONS

[Lil Abner]

Originally Posted by CueBall

I installed my tach today. The light works, but the tach doesn't.
I know I have power and ground because I can test those with my test-lite.
Is there any way to test the tach signal circut?
I am useing the tan wire furthest to the left on the OBD connector, as shown in this thread.

I get no lite with a test light on that wire, but my volt meter reads about 6.8v.

Well, the tach signal needs a solid ground in order to work. That being said, are you sure you don't have your positive and negative wires flipped? Also, HOW did you tap into the tach signal wire? Did you use a BLUE t-tap or scotch lock?