why might both headlights fail simultaneously?

[Norfolkandchance]

My 2007 Mercedes B Class switched its lights on automatically as usual and then immediately displayed an error message that the dipped beam on one side then the dipped beam on the other side weren't working, which they weren't. Main beam and rear lights all fine.

I've had a look for the fuse but the list that tells me which one is which doesn't match-up with the actual fuse box!

Of course it could just be the two bulbs but it seems unlikely. Should I start by replacing them and see what happens?

Thanks

[Norfolkandchance]

Thanks for all the replies. I replaced both bulbs and they are now working.