I had mine installed over the weekend in an '08 GMC Sierra, and the 'night display' function for the navigation was not working, so I look it up in the manual and figure the guy didn't hook the orange/white wire to the lights. Just got back from talking with him and he told me that everytime he hooked it up, it blew the fuse. So he supposedly called tech support who told him there is an issue with the '07/08 Chevy/GMC computers that cause that to happen. Sounds like BS to me, but I wanted to check around before I raised too much hell. Anyone ever heard of this problem?

Never heard of this, but why couldn't he just run a wire directly to a parking light??

Why a parking light? Wouldn't that activate the night display anytime a parking light is activated? That wouldn't be good.

Just hook up the illumination wire. It does work. Best Buy has a bad habit of not hooking up the ill wire due to it blowing up everything in your vehicle, edging on high gas prices, causing global warming, and clubbing baby seals. They told me that if I hooked it up in my 08 ram that it would cost me hundreds of dollars in new gauges, dash lights, etc. Guess who didnt listen to them, and guess whos truck is still working fine after six weeks of the install. The way I see it, if the harness provides an illumination to connect to an aftermarket head unit, then whomever made that harness evidently intended for someone to use that wire. If its doesnt, tap into a wire in the headlight switch that provides current when turned on. Thats all the D3 is looking for, a current that says "hey lights are on, dim down...."

Why a parking light? Wouldn't that activate the night display anytime a parking light is activated?

I installed a D3 in my 2008 GMC 3500 just a few weeks ago and hooked the ILL wire as the instructions state. All works great!