Main battery cut off switch blinking.

When I turn off battery power little red light blinks continously and also on firewall next to some kind of block of posts. Truck won't start and i replaced starter and disconnected all batteries and dielectric greased them due to green corrosion. After disconnecting batteries truck starts once and process starts all over. please help. Before this you would have to turn key on quickly three times to get truck to start. Now doing it in other 2012 cascadia with cummins engine. After looking closer to blinking light on firewall, found it is a fuse box and the fuses were laying out in side box put fuses back in but same problem

 

400 dollars. Don't understand this. 50 k miles. Why not just put big on off switch on battery cable? Special order too. Is this Cummins or Freightliner idea?

 

Changed the 400 dollar pndb and it still won't start and it is still blinking. checked auxilliary pndb and it has power going thru it.

 

Changed that too also ignition and relays. The only thing left on schematic is clutch switch and I can't find it.

 

It was the clutch switch!