When the rocker switch is in "OFF", the solenoid works from the run circuit and key.
Nope. When the rocker switch is in the middle position (it is 3-way), then the solenoid does not work at all. Rocker must be in MOM or DUAL to energize solenoid.
In key postion "ON" (but not in "START") you are already in "DUAL" (at least in my rig which has no rocker switch)
If you have no rocker switch, then I don't know how yours works.
With the rocker, it must mean you don't get "DUAL" just from powering the solenoid, you need to push "DUAL" too. But why should that mean the rocker needs to get any power from the run circuit to pass along to the solenoid, which is already in the run circuit?
The rocker is a 3-way switch. In the middle, it's off. When locked in Dual, it routes vehicle run power to the solenoid. When held in MOM, it routes house battery power to the solenoid.
The rocker switch will "stick" in the middle position (off), and in DUAL. It's spring loaded in MOM, so you have to hold it in MOM.
Does that mean the rocker itself needs 12v power to go from "OFF" to either MOM or DUAL?
12V power is what the rocker switch diverts to the solenoid. It's either getting 12V power from the house battery (MOM), or it's getting 12V power from the engine battery (DUAL) when key is in RUN.
All the 3-way switch is doing is letting you choose the power source for the solenoid. That's it. DUAL picks up power from the engine battery (if ignition is in RUN). MOM picks up power from the house battery. And of course the middle position is "OFF".
