For all those about to buy Metra - carefully study the pin-out positions and match them to your vehicles factory OEM pin-outs. Why, you ask? My 2007 Mazda 3's Metra harness is incorrect. Metra confused "dimmer" with "illumination" for the head unit lighting trigger.

Why is this a problem? According to Pioneer, the dimmer circuit has fluctuating voltage, as opposed to the illumination circuit. They think it's a bad idea to hook up their head units to the dimmer circuit, as it may cause damage.

Oops - too late for me. My "brick" from a few days ago was wired to the aforementioned dimmer circuit, as per Metra's written and telephone instructions. Not good.

If anyone wants to chime in on the technology here, please do. I'm just relaying what Pioneer told me to do.

Maybe the Pioneer people are wrong, but I have one dead unit which suggests they're right.

Curious, whats become of Le "Brick" as I just installed mine using a metra GM harness

Metra harness's are usually pretty good from what I can tell. The one I used on my Lexus didn't even have a wire for the illumination, I had to crimp the unit's illumination wire onto the stock radio illumination wire.