Somehow I got the notion that when you turn the key to Start, that cuts off the blower motor etc including the power to the solenoid from the engine battery.
That is correct. When you turn the key to start, usually all RUN accessories turn off. If the charge solenoid is powered by this (mine is), then it won't be on when switch is set to DUAL and the key is set to START.
With MOM you get house battery power to the solenoid, not any engine battery power if I got that right.
That is how I understand it, yes.
So with MOM when you turn the key to Start it can cut off Engine battery power to the blower and solenoid, but that power is now from the House, so it all stays on is what I assumed.
No.
With MOM all you are doing is ganging the house batteries to the engine batteries. The
charging solenoid is being powered by the house batteries. But everything else normally run by the chassis system (blowers, radio, etc.) are controlled by the ignition key being in RUN. So they will be off in START even though the house batteries are ganged to the engine battery.
You are saying that with MOM, the key in Start still cuts the house power to the blower, but leaves the power to the solenoid on so it stays closed.
Yes.
So even when on engine battery, all normal, turning the key to Start cuts power to the blower as one event and separately somehow on a different line somehow also cuts the power to the solenoid.
Generally, all non-essential accessories are turned off when the key is set to START. This includes the charge solenoid. But when you are holding MOM, it "overrides" the ignition switch power and instead uses power from the house batteries to energize the charge solenoid.
MOM is able to distinguish between these two events and only cuts the power to the blower and not to the solenoid?
MOM doesn't cut the power to accessories - your vehicle's electrical system does (ignition key). All MOM does is gang your house battery and engine battery together. What electrical things are cut off when the key is in START is up to your vehicle.
You can think of MOM as simply a set of jumper cables from your house battery to your engine battery.
