Which harness? there are at least three wiring harnesses in the engine compartment. Copied From bbunt302
Just for reference, here's a list of all the compatible years:
Main computer to engine wiring harness:
89 harness should work for 86-89 as long as you're using mass air.
90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)
Late 92 through 93 harnesses should be compatible (single dash connector, fuel pump relay under the hood)
Diagram courtesy of Tmoss & Stang&2birds
I don't have access to a picture of the body wiring harness, so you will have to guess what that one looks like.