My 1989 mid year ranger is having an issue too where the windshield wipers wont turn off
its rather annoying and i'd love some suggestions on how to troubleshoot this issue.

thanks in advance :)

 

Welcome to the forum

I don't have a wiring diagram for 1989 Wiper circuit

Fuse #2 powers the wiper switch so you can pull that fuse and wipers should shut off

Best guess would be the switch itself has failed and won't cut power

If its the Multi-function switch then thats the most likely problem

1989 to 1994 used the same switch as far as I know

diagram below

 

Sounds like the "PARK" switch in the wiper motor has failed.