Electrical Engine Harness swap 1989 car 1991 harness?

[Bluto65]

I have a 1989 mustang 4cyl. coupe and a 1991 computer and harness. Can someone tell me what I have to change in the harness to make this work?

 

[Mustang5L5]

biggest change to fox wiring was 1990. Colors, plug locations, physically plug differences. The two major year spans (87-89 and 90-93) don’t interchange easily.

You would have an easier time finding an 87-89 engine harness, easiest time finding an 89 harness.

 

[AeroCoupe]

Go here and Post #3:

4 cyl. to v8 swap what wiring

on a 4 cyl to v8 swap,fuel injected,do i just swap the engine harnesses and computer or does all wiring have to be changed?need help and advice

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