You may actually have three solenoids, 1) latching solenoid for battery DISCONNECT; (some) use a mechanical on/off battery switch); 2) a continuous-duty CHARGE SOLENOID; 3) a continuous-duty BOOST SOLENOID. The USE/STORE SWITCH AND LATCHING SOLENOID use coach battery voltage;
if BATTERY TOO LOW, it will not work. Should ONLY be turned to STORE/OFF if stored without being plugged in. Otherwise, leave in USE position so battery can charge from CONVERTER. RUN ENGINE FOR a bit to charge, then try USE/STORE SWITCH AGAIN?
2000 Conquest LE 6266, Class-C on 99-E450SD, 6.8, 2v, V-10