wiper motor style and replacement

Maybe a Denso?

https://www.amequipment.com/

These are the go to folks for all things RV wiper related. Great phone help too.

sounds like the park switch inside the motor is making contact, or the wiper switch is going into pulse mode. maybe a trip to the local wreaking yard may find its a common wiper motor asmb. used on other Gm trucks. There is a printed circuit board on the wiper motor that controls the speed and the pulse function that i have also seen cause problems from water damage as well.