I may be wrong but it worked for me...

I was debating if I wanted to hook up my illum. wire because it was so bright at night but I noticed something. When I was playing around with the dimmer setting at night I made it to the lowest setting, then before I turned off my car, I turned off the lights and it got brighter. So I decided to turn on the lights again and my screen got brighter. Which got me thinking...

Isn't the illumination wire exactly for that purpose? So when at night it gets dimmer? So now for me, I set my dimmer setting to the brightest setting during the day and the darkest setting at night. Which is exactly what I wanted. For me, I had to adjust both AV and MAP settings using the "V" button on the bottom.

Hope this helps people, I figured I'ld do my part if this helps anybody. Alohas!

why would you want to have to keep changing those settings? if you hook up the wire it changes automatically

I personally don't like the display in night-time mode. Also, I like to have the parking and fog lights on during the day. I have the Illum wire hooked up, but I changed the setting to not switch automatically when the lights come on. Now, at least I still have the option to go into night mode in case my passenger cries.

theres a setting for that, i believe for your exact purpose, it wont go into night mode but it will still dim. say when you need to turn on your lights for driving in the day.

night mode and dimming are two different things

There is a day/night button on the nav screen that you can press to change it to day. For some reason it doesn't change day to night. only night to day.

Let me see if I get this point right.

With the ILL wire hooked up....you drive off down the road and it starts to piss out. The wipers come on and in some cars this will turn the lights on automatically even if it's still quite bright out. So the unit will know if it's day or night versus having the lights on all the time?

And if you are someone that turns the lights on during the day or long trips, the ILL wire won't be dimming the unit?

yeah