Doing without the light is definitely no cut- I'm not certain about the connection in the light- it could be two wires in the same connector (require cutting), or two disconnects on a twofer, which wouldn't.
FWIW, I doubt any service place would deny warranty because of cutting that wire- something like that is kind of a "don't ask, don't tell" thing- if it obviously didn't cause the problem, we just don't mention it to Dometic :).
I've known boondockers who disconnected the light and put a battery led tap light in the box.