Swap black and yellow? Uh no................
I would pull the yellow loose at the starter relay. Then troubleshoot "in safety." With prior harness "meltage" you might have something crossed/ welded in the harness. Or it might just simply be a defective switch, which has been reported by others, or since I'm not there it may fit so poorly that is causing the thing to trigger the yellow
OR MAYBE someone improperly rewired it
ON THAT NOTE check and perform the bypass on your seat belt interlock. The yellow start wire is interrupted on the road to the starter relay by the interlock device. This is a box about the size of a horn relay over on the inner fender some place with a push button (used to be red) reset. You will find two "yellowish" wires. You need to permanently splice those together.
