did you originaly have xenon ?
BMW Check Control will power the source then cut the power if something is wrong, like to low power consumption or so, you can usualy buy aditional cable from your balast suplier to trick the car system

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X5 4,4i-06 Current
330Ci Cab-03 2007-2008
MB E55 AMG-03 2006-2007
Z3 2,8 Roadster-98 2006-2007
X3 2,0d-05 2005-2006
320d-99 1999-2005