...and in some coaches there is an actually 'switch' on the dash that allows the radio to work, outside of the radio's own on/off button... this way you can tell the house batteries to provide the power, when parked, versus the chassis batteries.
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada - Hiawassee, GA! (also, '14 Gulfstream Amerilite and '07 ForestRiver Rockwood) : )