When I turn my headlights on, the interior lights don’t change, I know about the dimmer, but the dimmer isn’t doing anything. Is there a fuse or something that controls this?

 

There is a sensor somewhere in the dash. Whenever it gets power, it triggers the dash and radio lights to dim.

 

Actually never mind my first post. Its not a sensor in the dash. Looks like its controlled by the BCM. When it gets power, it triggers all the displays inside to dim. BCM terminal 55 is the sense line.

 

If you have NAV you might have a "brightness" display button on your control panel? It looks like a sun and a moon. There are two settings, one for night and one for day. Maybe try messing with that. Here's info from an '06 sedan owner's manual:

To change the display brightness, push the [sun/moon] button. Pushing the button again will change the display to DAY or NIGHT display. Then, adjust the brightness by moving the joystick right or left.
If no operation is done within 10 seconds, or if the “BACK” button is pushed, the display will return to the previous display.