The donor harness is from a 98 Z24 first I was told it will be fine, now I'm being told it will need to be re-pinned. everything that didn't work before now does with the exception of the turn signals and hazards.
99 headlight harness and engine harness is 99 only. You can modify the 98 to work, but that is why your turn signals and hazards are not working.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
I looked up some diagrams, it's looks like it's two wires that are different, one says "+ battery voltage", the other says "left headlamp fuse/drl relay", all of those work fine.
It is for sure more than 2 wires different. You may have to trace each wire to correct the issue.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Ok, so if I was to unplug the front harness, would the dash and rear turn signals blink? I imagine they would, but faster than normal, because it thinks the fronts are burnt out.
Yes.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
just tried it with the front harness unplugged, no change.
Update: It was the flasher cube!