Where to tap dimmer switch

Hey all,

Installing my AFR/Boost gauge combo from innovate Motorsports. I need to find a tap for the dimmer function tied to the headlights being switched on. Any ideas? Or run a fuse tap off the headlight fuse under dash?

can’t find any wiring diagrams and I’m terrible at reading them.

Thanks.

 

You ever figure this out? I installed an external oil cooler. And it has a temperature probe ports. I'm using the Bosch electrical gauge that comes with a back lit bulb. The G wire is always constant 12V to ground. Using a multimeter when I back probe the W-G wire terminal on the Rheostat turned all the way to make the lights brighter and ground to left kick panel ground the voltage reads 0.15V. When the rheostat turned all the way for the lights to be the dimmest. The voltage reads 12.5V. Which doesn't make sense to me.