no power to map light

Extra fuse panel on a MH to me would indicate possibly a fuse in the house panel. In other words at the converter.

Check all of the 20amp DC fuses under the refrig panel. If yours are labeled better than mine you are in luck. I don't think it is in the fuses on the dash in front of the steering wheel. The third place to look, in fact start there, is above your left foot as you drive. Upper left corner under the dash. Lots of small fuses in a gang of fuses about 4X5inches. It maybe attached to the firewall but can be unscrewed and pulled out a little. If you have a drivers door it is easier to reach with a small ladder. BTW, BTDT, mine has two switches, both of which must be on to work, the little one on the light fixture and the toggle on the dash. Good Luck.

Try reversing the wires to the LED fixture. LEDs are polarity sensitive and will work only if installed one way, unlike the original fixture.

Since the map lights might turn on with the headlight dimming switch, I would look under your dash, to the left of your steering column, for the fuse box. That is where you will find the fuse.