Replaced under hood fuse block; no crank from starter

team
the story:
the truck starts and runs but the fuse block housing (plastic) under the hood (relay #2) is smashed broken and unsafe.

I replaced it twice (2 separate unique blocks) Toyota salvaged fuse blocks with the complete wiring harness attached (no need to splice).

the result is everything lights up and works, but it wont crank. no juice/power to the #2 input on the starter relay/fuse in the main block when I turn the key. I do get juice/power to the #2 when the original harness is installed.

if I re-install the original, busted, harness it starts and runs.

any idea why this is the case?

POSSIBLY IMPORTANT NOTE:
when I install the new harness, I make all the connections inside the cab/under dash, all the engine wiring and battery stuff, but I don't insert the bulbs or tie in the final ground from the front end part of the harness (this is the harness that runs just to the headlights, horn and turn signals).
I didn't think this mattered.

TROUBLESHOOTING
I thot it might be the park neutral switch, but it seems to be fine since it starts in P or N (and not in R, D, etc) when I have the original harness attached. so I think that means the P/N switch is functioning fine.

any thots?
any help would be great.
thanks,

cd