The $15 part is the seat belt warning emulator. You may need the seat sensor bypass part as well. Small grey box with a couple of dip switches. Both work together as the seat thinks someone is always in it so the seat belt warning needs to be tricked. Also, many of these cars were covered under a recall. Mine was not far a strange reason but 90 percent were...check that out first.

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2006 BMW x5 e53, M54, steel grey, black leather, pano roof, cold weather package, avic-z150bh head unit with JL Audio amp and speakers.