We have an issue where if we park the car nose down and out in the driveway, the alarm will go off a few times a day on bright sunny days (ambient air temperature varies and doesn't seem to change behavior). If we park it nose up, which sees less sun, we never have a problem. Ever. Strangely the same behavior is exhibited by our f15 x5. Have done no actual diag but the sun seems to be triggering a sensor somehow.

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)