Where to tap lighting for boost gauge

[DeusExMachina]

I'm mounting the boost gauge on the steering column of my 1991 Legacy Turbo. I want the backlight to be on only when the headlights are, and don't need any fancy dimming switch or anything.

Could I tap the power to the lead for the headlights on the lighting stalk's harness? I'm looking at page 18 in section 6 of the factory service manuals. It says continuity over wires c1, c2 and c3 for headlights, c1 and c2 for tail lights. Could I tap wire c3 for the boost gauge lighting and ground it somewhere?

[Legacy777]

Tap the illumination wire on one of the switches, ie cruise or rear defrost....or even run a wire over to the radio.

The backlight will go on when you turn your parking/acc lights on.

[eastbaysubaru]

I hooked mine up to the illumination for the cigarette lighter. Very easy to get at.

-Brian

[QuickDrive]

I used the ashtray light to tap into.