I can not help you with where the fuse is. However, this is a possibility you may not have looked at. Many coaches have a master switch that provides power to all the lights. This allows the coach owner to turn the lights off/on from inside the coach and in each compartment. If this switch is off, none of the basement compartment lights will come on. Don't know if this could be a quick fix, but I'd feel bad if I didn't mention this and you posted that was the problem.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
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