Worth mentioning that 2004 and onwards may require coding by the dealer to allow the vehicle to recognize the trailer wiring module that you installed in step 12. Earlier X5s didn't require coding (my 2003 didn't) but it appears to depend on the specific software that your vehicle has, whether the module is recognized or not. If not, trailer wiring and PDC cancellation will not function correctly.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue