does this M880 still have the dial switch on the dash that controls the blackout lighting? The wiring is often all done in what looks like brown lamp cord, with little numbered aluminum tags crimped to the connections?

I know this dial switch caused a lot of issues on a friends truck. It would not crank, or fire at times, or other odd electrical issues would pop up.

He carefully removed all the military add on harness, and restored to the factory and the problems went away.