Which headlight switch wire to tap into?

Loco5.0

5 Year Member
Apr 2, 2005
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I'm going to redo my Auto Meter tach wiring. Which wire coming off the headlight switch (LX so non-fog) should I tap into for the light wire coming from the tach?
 
Can't remember the color...I am sure someone will chime in with the diagram. But the easiest thing to do would be to probe the wires with a test light, the one that powers up when you turn the headlights on is the one you want.
 
It was one of the corner wires... lower left corner wire, maybe one up.....light blue wire, I think with a red stripe. That's the one I tapped into for my dimmer function on my 86.