Added some inexpensive gauges to the 355W. I don't know why Jayco doesn't install something like this from the factory. I have one gauge for each leg of the shore power, and the center gage records draw from the 12VDC bank.
These are from amazon: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Those are interesting, but an EMS would not only tell you about your 120 system but protect if and your RV from many threats. Over/under voltage, surges, reverse polarity, open neutral etc.
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2011 Toyota Tundra double cab
2015 27RLS