I just installed a Valentine 1 in our new 2009 X3, tapping the mirror power lead, so it's mounted high on the windshield, near the mirror. It was easy to do this once I found the right wire (using the online wiring diagram system at WDS BMW Wiring Diagram System - English) which is the green/white in the bundle going to the mirror. (If you don't have the photochromic mirror with the universal remote and compass, the wiring should still be there and be live, I believe.)

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Radar detector power - bimmerfest - BMW Forums

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