If you leave say, the door open for quite a while (not sure of the exact time, I say 20 minutes), the car should cut off the power to everything including the power seats and even the two-piece glove box. However, you just need to press the power button once (preferably without a key-- with a key and acc is on) and everything will receive power.

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2012 BMW X5 xDrive35d
Alpine White | Sand Beige Nappa w/ Leather Dashboard | Light Poplar | Premium Pkg | Sport Pkg | Premium Audio Pkg | Tech Pkg w/ HUD | Multi-Contour Seats | Heated Seats | 20" Wheels | Soft-close Doors | Running Boards | Spare