2015 D5 dipped beam malfunction.
 

My passenger side headlight stopped working suddenly. I swapped the bulbs with working ones and it still did not work. I thought it must be the ballast on the xenon headlight. I swapped the working one from the drivers side and it still didn’t work, not only that but now both are not working. I have ordered some new ballasts but am afraid that the passenger side one is just going to break again. I have checked the fuses and also the wiring but not the main thick grey wire connected directly to the bulb. I’m not sure what way to turn now. Could it be the wire that needs replacing or should it be ok with just putting a new ballast in the passenger side. The ballast have the same part number and are ballast 7 green. The bulbs are D3s.

Try new bulbs first.