Your best bet is to buy a Ford EVTM (Electrical and Vaccum Troubleshooting Manual) or the full shop manual for both years. (You're swapping a 1989 to a 1996, right?) The EVTM is much cheaper. I used to have one, and it was great - wiring diagrams for virtually everything, plus testing guides. I think it is mostly excerpted from the full shop manual. Try Helms, Inc. or eBay for sources.