Hi, when you say it does not work do you mean that you tested it with a meter and there is no voltage, or that an accessory plugged in does not work? If you don't have a meter go and buy one. They cost about $15 and are really useful for RV owners. Put the meter on DC Volts 20V, put the red lead in the center of the power port and the black on the rim. If no power the first thing I would try is to put a new fuse in the empty 72 slot and see what happens. Minimal risk and might work. Maybe the shop took it out? The looking under the dash suggestion is a good one - on RVs things vibrate loose a lot.