Originally Posted by cgr406

So i found a wire in the largest of the four connectors that go into the audio head unit that controls dimming. This wire carries 0v if the headlights are off & 12v if they are on. It's the one circled in the attached picture. It's a red wire. This is for a 2014 w/ Bose but w/out nav. I test connected this to the dimming wire on my VEI gauges & it works perfectly.