this depends on rariety and how badly you want it...
if you can get your own harness at a U-pull-it expect to pay $20-$40
for the harness itself. and $15-$50 for the PCM
However if you are getting it from someone who is going to
go pull it for you, expect to pay a bunch more.
Consider the time nd effort getting the harness out
AFTER driving to the junkyard, LOCATING the proper harness
Boxing it up, etc...
If you find someone willing to sell you a harness and computer for less
than $150-$175 for a specific application.... well lets say you're receiving charity.
Typically 4.0 harness for earlier vehicles are harder to track down.
4cyl and 3.0 harnesses? ENTIRELY different discussion
People are pulling those off and some packrat might not want to
throw one away... but...
AD