Guess that explains the funky relay box on the backup camera I just bought for my x5.

It has a positive and negative that come from a key switched source and then a positive and negative that go to the reverse light wires themselves.

When I was testing it about 30 minutes ago it took all 4 wires hooked up to actually power the camera. That would give 100% isolation from the voltage testing the car does.

__________________
Just BMW's - All cars and trucks was two pages long
1994 318is
1997 528i
2000 323i
2001 X5 3.0 auto
2005 X5 3.0 auto
2011 535xi auto
2013 X5 xdrive35 Turbo
More are at my website

Aftermarket E53 Radio Install