I feel it is something between the headlamp switch and the body control module. However, which is the likely cause is the question.
Here is what I recommend. Have the vehicles can-bus scanned to see if there are codes stored in any of the modules.
CAN stands for controller area network. Basically, all the different modules in the vehicle are tied together via a few wires. A traditional scan tool won't retrieve codes from most of them. This type of scan will retrieve codes regardless of the module storing them. In this case, it would be related to the body control module (BCM).
Here is a link that explains how it's done. The reason I'm suggesting this is because otherwise, it becomes a guessing game.
Let me know if this is something you can have done.
Sunday, November 27th, 2022 AT 10:22 PM