If you have modified the unit is it possible you allowed high voltage to arc over to other things? That could fry servo motors and ruin the ballast. It's hard to play doctor from far away. Try switching the ballast and see if the lights come on. Do you get voltages across pin 2 and 3 of the ligh plug. If not it's a fuse or something further up the line. You need an Ac volt meter for the servo motor tests or better still another lamp unit (Ebay) or an oscilloscope. If we were close I'd be able to help out more as I have the equipment and diagrams.
Check this out.
http://www.xoutpost.com/articles/x5/l...53-2004-a.html