When you say the "main panel inside" I take it to mean the coach 12 volt distribution panel. If this is correct. All of the fuses will be supplied power via the battery and/or (in some cases) the charging system; as long as the over current protection device and/or battery disconnect solenoid are not open. Check both sides of the fuse. If you have power on one side but not the other then the fuse is blown or has a bad connection. Also make certain that you have a good ground on your test light or meter. Verify by check other fuses. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7