Had an X920BT put in my 2001 Infiniti Q45 at Best Buy. The screen is blindingly bright at night and does not dim when I turn the headlights on. Manually dimming from the screen adjustment menu doesn't help much. Also, the nav map will not switch to Night Mode even though I have Night Mode turned on (set to Automatic). The installer says there's no "headlight wire" to connect the unit to. How should he connect the illumination wire? And is that what triggers Night Mode in the map display? The nav unit clock is set properly but even at midnight, no Night Mode. Just an insanely bright white rect