Old Man Mike

No modifications to the harness. The bulb is coming on when not expected (and the other one is not doing this). Are the harnesses for all 4 bulbs wired alike - ie do they all have DRL, low-, and high-beam running to each bulb?

I have a 2018 Ford Edge Titanium with 90K miles. While driving with daytime running lights or low-beams on, the passenger side high-beam comes on & off intermittently (a few seconds at a time - not a flicker). Both high-beams come on when selected (no noticeable on/off behavior). I've not been able to reproduce the problem with the car parked and idling (or banging on the housing). This was after an unsuccessful attempt to switch all 4 bulbs to LED (they would not install vertically and were not adjustable so the original halogen have been re-installed). Thoughts on how to diagnose and fix the problem (switch, relay, control module, wiring, bulbs)?