A worn motor could be the issue in some cases, but IDT that's the root of the non-parking w/s/w issue in many cases (even replacing the board). But please report back what you find out on yours. I'm interested to hear.
There is/was a whole segment in a GMT manual how to re-set the 'park' on the wipers. Sad to say, I can't remember what yr manual I saw it in. It's been a long time. Obviously there's the issue with the traces corroding on the board, and what board did you get (import or a 'good' one??). And make sure the body grounding (and wiper/wiring ground) is good on your truck too. The juice goes from Neg -> pos, lol. Have you checked youtube for some help?
