[s-cars] troubleshooting aftermarket HID's

[Erik Addy]

The PO installed euro lenses and HID's my S4, but the drivers side just quit working.
 
Is there any easy trouble shooting technique to discover if it is the balast or bulb capsule?  Or am I just better off buying one of those cheap DDM HID kits and replacing both sides?
 
I suppose 4500K would be the best lighting performance?  35w or 55w?  
 
Thanks,
Erik