My point was unlike the beliefs of many, you do not have to buy the factory wiring harness. I have this: http://www.amazon.com/Hopkins-46255-...0573196&sr=8-1

It does tap into the factory wiring behind the rear lamps, but the main power is drawn off of the battery so that it will not cause "bulb-out" warnings. This will get you a 4-flat connection. I then purchased from a local auto parts the 7-blade round plug/ four-flat plug that mounts next to the hitch (I will have to get the info on this unit). On the backside it had a four-flat connection that plugged into the unit above. I just had to run one additional wire to the backup lights to get all the functions I needed.

I have never had a bulb-out warning light come on while using this setup.

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2001 X5 3.0i (PP/WP/AP) Traded at 213K miles
RARE White on Black - Why does everyone get Tan??
First E53 with 215s on XOutpost!!