take the harness even if it is buggered. i don't know exactly what year the switch is but i think the under the hood harness may be a 2-3 year only harness so you may only find it on the 90/91 trucks and some 92's that have the 360. you may have no choice but to fix it if wanted to run the TBI. i believe the 89 and older harness's are different than the 90 and newer trucks so anything 89 and older would not be plug and play capable.