Other than the general rearraingment of the Ranger Wiring harness
which had some obselescence issue due to originally being designed
for a carb 2.3, the primary change to the 1989's was eliminating the
fuse links and replacing them with Maxi-Fuses in the underhood
load center.
Funny thing was a few years later after ALL the fuseable links though
I seem to recall that there are a few hidden somewhere I can't recall where at the moment.... anyway after they really had been eliminated ford put one
(or two on some vehicles) back in, incorporated in the alternator harness.
So I'm not sure your 1989 actually has any.
For whatever it's worth there are NONE listed in
my 1989 EVTM for the Ranger/Bronco2
AD