Does your coach use the RV Custom Products BCC (Bat Control Cabinet) ? You said that you jumped the Aux solenoid under the hood......do you mean that you operated the Aux switch at the drivers seat which then operated the battery interconnect relay and then you can start OK?
If you have the RV Custom Products BCC I would first ensure you have Chassis battery voltage where the battery cable physically connects to the BCC cabinet.......ensure tight terminal connections on both Chassis battery and on BCC. The coach battery seems to be OK as is the path through the interconnect relay and latched chassis relay in the BCC.
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