I recently installed an AVIC Z1 in my 04 Chevy Avalanche. The installation went very smooth except for when I was done the stereo didn't dim at night. After doing some research I read that a lot of people forget to hook up the orange with white stripe dimmer wire. I pulled the stereo out and I had in fact hooked the orange and white wire up to the orange and white wire on the adapter. After looking closer I realized that even though the adapter had the wire it didn't match up to anything on the factory plug. I spoke with Crutchfield and was informed that the Bose system does not have a dimmer wire on the harness and that the orange and white wire needs to be attached to a wire that turns hot when the lights are on. The tech told me to tap into a brown and white wire that goes through the firewall that comes from the headlight control switch. This seemed like it would be a challenge to find so I went direct to the source. I removed the dash and pulled out the headlight control assembly. This assembly is held in with clips like everything else. If you pull on it gently with a little bit of a wiggling motion the entire assembly will pop out. I tapped into the brown wire with the white stripe and ran that to the Orange and white wire. Victory! My stereo dims when the headlights come on. I have attached pictures to show the assembly and the wire tapped into.
Hope this spares some headaches for others. I had extensively researched the install of this stereo and had seen no mention of this.
