I do understand that the switch does not need to be wedged when the engine running. I would like to know how the system determines whether or not the engine is running..?? It's not just a matter of having the key turned on... this does not of and by itself energize the relay... thus the need to hit the switch on the dash to tie the batteries together to get more juice for starting. So what kind of control strategy is used to determine whether the engine is running? This is an old 12 valve cummins... no electronics on it...
You start the engine and a relay delay is energized after the chassis batteries reach a pre determined voltage which usually takes seconds. My relay delay has failed several times and taken the isolator solenoid with it each time . The last failure I decided not to replace it and instead, operate the booster switch manually while driving. I have to put a reminder somewhere to make sure I don't leave the batteries connected while parked because that will burn the solenoid out and/ or run the chassis batteries down while boon docking.