Where are the settings stored?

[walkabout]

G'day
I have a 2002 model with the comms pack, does anybody know are the settings for the Screen, like Brightness, contrast, volume stored in the screen head unit itself or in the CD/DVD unit in the back?

I have a screen brightness problem, the screen will not remember the settings, it keeps defaulting to 50% on startup.
My Dealer says the settings are stored on the CD/DVD unit in the back, and want's to replace it under warranty, but I thought the settings were stored in the head unit with the radio station settings e.t.c.

anybody know for sure?

Thanks

[Chip]

After presing Accept when starting the car, use the right knob to get to the Settings page and push it in. Then, go to brightness by turning knob

[walkabout]

chip
That is not the question I was asking!
I know how to change the brightness, that's how I know it's not holding the value.
If you read the post, I am asking where are the settings physically stored.
Do I replace the head unit or the DVD/CD unit in the back of the car?