The computer only only controls the engine and fuel pump and no other accessories.
It sends RPM information to the tach.
Here's a book that will get you started with how the Ford electronic engine control or "computer" works.
Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.
It's about $25-$50 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search. Try searching using M-1832-Z1 instead of the ISBN number if you don’t get any positive results. You may only be able to find a used one, since the book is as old as the cars it covers. Or you order it from your Ford dealer as SVO part no. M-1832-Z1.
Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.