Hi, though it is difficult to get hold of the complete set of factory workshop manuals which includes the electrical wiring, however; many state libraries do have complete sets of most holden factory workshop manuals to look at, though they cannot be lent out. Wiring is not all that many pages so you can still photo copy them.
For others, maybe this link will help.
https://www.carpdfmanual.com/holden/#google_vignette
They seem to have the basic wiring diagrams for all VR and VS versions, though I can't compare them with anything else. Maybe it is just an after market version, but it may help.
I actually designed several of the electronic circuit boards used in the switches for the VR and VS models back in the days.
Kindest Regards