I’d probably start looking for a wiring connector that is common to those circuits. Possibly a corroded connector that is leaking current to another circuit?

 

Pulled some stuff apart and it looks like the Bcu got wet at some point.. little bit of corrosion on the plugs but who knows.
Too close to the Ecu for comfort aswell.

Time to play the game of chance on ebay used parts I suppose.

Anyone got a known condition/mileage Ecu Bcu set sitting around?

 

Maybe you’ll get away with cleaning the contacts? Also I would look into what caused the corrosion. Water leaks? Mine came at scrap price due to a corroded ECU from water leaking into the heater fan inlet.

 

Trying to fix this unintended kill switch I finally replaced the BCU today.
The one removed was actually in better shape then i thought with like 2 corroded pins.
And after bricking my truck a few times with the nanocom, reprogramming keys and such it runs and operates well.

Except the fact that the unlock on the dash still kills the engine.
Gotta be a pretty serious short/ground going on somewhere in the circuit.
Gonna go all csi on the rave electrical diagrams tonight, got em on my tablet finally.

Im tearing into every electrical box and harness rub/connection point i can find tomorrow. Ugh