The appearance of a blown fuse can give a clue as to whether or it failed due to a direct short to ground or due to a slow build up of heat from a failing component like a blower fan or high resistance connection.

Look at the ends of the severed part of the fuse. Are the ends melted with a glob shape? If yes, there was a slow build up of heat from a component failing and drawing excess current or a bad connection in the circuit like a plug/connector that is loose.

If the severed ends are sharp/crisp it was a sudden high current draw probably due to a chafed wire as stated by previous members. Sometimes they are even sent in opposite directions.

It is common that the last repair is the problem, the headlight switch was replaced recently and is on that circuit. Can you swap it out with another one?

Good luck!!!

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