I have no idea what that wire is or if it will cause a no crank, but my guess would be that yes, if it were broken and it connects to the starter that it may cause a no crank situation.

The ECU and the BCU must "talk" to each other, if they dont match then the truck wont run.
It is all part of the anti theft system for the truck.
So no, you cannot just replace the ECU or the BCU and expect it to start.

 

jump the starter relay to see if it starts.

if it starts then its electrical. that means the system isn't seeing a signal like say a xyz switch or something else.

We can use a handheld and check out the system without hooking up testbook if the guy knows his stuff.

but basically if you power on both sides of the relay and the good ground at the relay then by jumping the relay you are getting around the bcu signal ground. If it stops running when it shuts off then by all means get it started and get it to the dealer cause we can see what is missing on the vehicle. Its possible you didn't line up the switch correctly as well and that it needs to adjusted just right.

if you want to throw in a xyz switch then go ahead. its possible you damaged it as well.

 

I am not sure too. Mine i changed the terminals and carbon. sorry. You might want to replace that. Does your starter have enough carbons?