Well if cruise is a standalone,and I don't see the pcm in the schematic, your cruise will probably work when you hook up the servo cable? You will probably want to install a clutch switch.
I'm still a ways off from cruise control, () haven't really turned a wrench yet.

 

OK next problem; The engine I have is missing the ser.no. plate. there is a gouge in the block where it mounts and it evidently got ripped off.So today i totally befuddled 2 different parts guys. any idea where other i.d. numbers might be? I guess cummins is a stickler for ser. numbers it is a 1988 model year but that doesn't help them. All I need is a oil pickup and pan gasket and belt tension-er. Thanks John