I have a 1988 2.5TD and I can't remember how the starter switch is wired. I have a photo from before it came apart (18 months ago!), but I can't make out the wire colours. The wiring diagrams don't show pin numbers :roll:
There are pins numbered 1 to 5.
The loom has the following wires:
Large brown
Large brown/red
Large white
Small white/red
Small white/orange
Small white/black
I believe the white/orange is unused on mine. It is for accessories, so I can graft it in if needed anyway.