I know you say your xenon light does not work but Does your high beam work ?
Have you checked that the earths points are ok, also have you checked the fuses in the engine bay fuse box FL8 and FL12 I think.
The engine bay fuse boxes are a known problem area with chaffing wires underneath and the fuse box internals rot and short out.
If the fuses are ok you are going go need to start to check for voltage and start chasing wiring
It is possible it could be the BCU but do the easy cheep stuff first
Hope this helps