20 years Old?
You have MULTIPLE problems in MULTIPLE systems. There isn't a COMMON denominator.
The best chassis wiring diagrams are factory. In your case, authentic FORD manuals
Start at GOOGLE. Search Box FACTORY SERVICE MANUAL your make and model
Many service manual providers offer one-time downloads of the entire manual for your chassis. They are worth every nickel. The "pages" don't accumulate greasy thumb prints :)
Your NO KEY START is probably in the NEUTRAL SAFETY SWITCH circuit. Try NEUTRAL instead of PARK.
rockauto.com has a lot of the electrical parts you will need.
A twenty dollar starter motor is like a ten dollar suit: Wear Underwear.
