The backlight on your LCD panel has failed. You'll need to have the unit repaired. I use German Audio Tech in Long Beach, CA...but you may have someone closer to you. Also, make sure the repair uses the correct LCD panel as some cheap options cause a viewing angle issue when you're in the driver seat...and that makes it hard to operate while driving.

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2003 E53 4.6is, titanium silver, black Nappa interior