It is most likely your circuit breaker panel is not labeled correctly.
I know mine isn't.
That having been said, the best way to trace the break is with a wire tracer (dog & bone) like the IT guys use.
Klein Tools VDV500-705 Tone Generator and Probe Kit, Wire Tracer and Tester with Probe Includes Alligator Clips and RJ11 / RJ12 / RJ45 Plug
https://a.co/d/8Zasa8G
If you are not familiar with them, check out YouTube or hire an RV Tech. Tell the tech what's going on to be sure he has one to trace where the break is.