Welcome to iRV2.
Isn't RV electrical fun.
Easy to tell that the guys building the RV never have to try and repair it.
Just a note on meter use ; and this isn't true for all meters ; when testing a fuse the way you describe , if the circuit is shorted , and the meter completes the circuit , you can burn it out, or at least over heat the wires .
If the fuse your testing is a single dedicated circuit with a switch , and the switch is off , you have no ground path and won't get a meter reading.
I prefer to use a test light; or meter; connected to a known good ground, when checking fuses ; unless you pull them out and use the ohm function.
Another note on meter use , it only takes mili-amps to give a reading on a digital meter , poor connections can pass enough power to give a reading , but nothing will operate because amps won't get through .
The fuse in the picture below, was not blown and passed enough power to give a meter reading and light up the led on the control panel of my leveling system but nothing would operate from the panel , test light used at the control pad connector, just glowed, and I found my problem.