Ford KA headlights problem

[unified]

Hello, I have a Ford KA 2006, and the headlights go off and on intermittently. Sometimes, the left is on, and vice versa, and sometimes, they both function as they should. I have searched for loose connectors, wire faults, insulation damage, etc., but I can't find what is wrong. I am beginning to suspect a relay or something similar. Is there someone who has experienced something similar? I will be grateful for feedback.
Kind regards
Chris
*I live in Sweden