Day time running lights don’t don’t always light up

Hello, it's just a guess, but there is a lot of power running through your headlight switch, and sometimes the switch or terminals at the wiring connector can overheat and even cause some of the plastic to melt. If this was my vehicle, I would remove and inspect the headlight switch and it's wiring connector carefully looking for any signs of overheating. Beyond that, testing will be required to find out why your lights are not operating as designed, checking for power and ground where appropriate.