Hi, well I don't know your coach but the engine not starting should have nothing to do with your manual TV antenna. You are probably thinking about lockout relays that prevent certain RV devices from working if the ignition is on.....like slides, TV, steps retract, etc.
Sounds like your engine starter system has a problem and it could be anything from a discharged chassis battery; bad ground in starter circuits; loose chassis battery connections; bad starter relay; bad starter motor; bad ignition switch etc. I am attaching a generic F53 starter schematic which is just to give you an idea of what a typical starter circuit looks like. The A marking in lower left corner......connects to the A marking near the top. I would first check your chassis battery to see if it is fully charged (12.6 vdc unloaded) and that it has clean and solid wiring connections.
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