Seems the Non HD force has only the Battery Disconnect in the Battery compartment. Also, where is the engine battery? In with the house batteries?
I am leaning toward a bad Boost Solenoid, since I have 13.4 on house bank, but cannot get the boost switch to allow the VDC to jump to the engine start circuit..
Next is a solar tender for when we store this winter..
Also, driverside cab step, what is that plug for? Engine block heater?