Main beam wont stay on
 

Hello!
My 2006 Sport edition 200CDI W203 has bi-xenon headlights and a day after i changed my head unit my headlights stopped working (not sure if this has anything to do with it).
I changed back to the original head unit but the problem persists.

When i turn on the main beams, they stay on for a couple of seconds before they turn off again by themselves, but the blue main beam indicator stays on. If i leave them on they turn themselves on again after a while but then just as quickly off again as before. I also get a message in my display saying left main beam fault & right main beam fault.

Any ideas on why? May it be a fault code stored that i need to delete before it works again after i changed the head unit back?