ML11 The one big question he has now is that there is no earth to the starter relay…..does anyone know where that is??
Yeah, it's in the engine bay fuse box.

The starter relay is 2/35.
PS: There's a number of subtle wiring changes between late 960s and S90s (as I have found out the hard way…)
PPS: You're tracing the pink-black wire from the starter relay - which passes through connector A3/G [1], to connector B5 [4] and then to [50S] at the PNP switch.
At the PNP switch - when it's activated, it gets its ground via [50] at the switch, which is the black wire from connector B5 [3], to connector A3/G [2], and then to the earth point known as 34/42, which is a 22-pin grounding location in the engine bay fusebox.