remember changing my -4 from good ol manual pull to electron power many moons ago... drawing was published in the RVator, then became part of the plans (windshield wipers motor if I recall correctly).
Guess it might be included on the relevant USB stick as sold by Vans nowadays
I updated the link. Let me know if it's still not accessible.
(Google Drive is extremely slow for me, and for some reason that file was set as restricted.)
Finn