The switch on my 42 is aftermarket (previous owner converted the truck to 12v and moved the switch lower on the dash) so it looks different but I believe functions as yours does. Mine is bimetallic so if it heats up from too much current it swings away from the contact, causes a break in the circuit. I reasoned that a dirty contact caused it to get hot and subsequently kill the lights. The lights would come back on after 2-5 minutes and on I would go, until they would go out again after a variable amount of time, up to half an hour. In frustration, during one of the outages I stuck my hand up around the switch in an attempt to find a loose connection, and felt the heat. I am not sure by any means this is what your problem is but I thought I would bring it to your attention.

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