Deleted first post. I found what I was looking for.
With the Kenwood DDX-512 and the 4Smartcar wire harness you can hook up the dimmer control. It does not seem to have a big effect though. You just have to make sure under the Kenwood setup you select Sync. I didn't hook it up on my first install so I just took everything apart and made the change. Only took 15 minutes.
For those that hate manuals here are the steps to control the dimmer function. Smart dealer told us we could change it. Oh well... They can't know everything.
Turn key to position 1
Turn on parking lights
Press button on right side of instrument panel (the one you use to adjust the clock)
Simply press the button repeatedly until you find the desired setting
Linear Mode
