Wiring confusion!!

[Al Housman]

I almost have the syncro back together and am just finishing the wiring but I seem to have a wire over and can't for the life of me figure out where it goes!
It is a brown/black wire with (I assume) a light brown earth and it's hanging down between the gearbox and the trailing arm on the left side.

Now I have put a blue/brown wire with again a light brown earth to the rear difflock activator switch. But there's a possibility that this may be wrong and maybe it should be the brown/black wire that goes there, although it would be a bit of a stretch.

If that is the case where might the blue/brown wire go? It is fairly long so could in theory go almost anywhere within the engine bay.

I'm pretty sure I have covered all options but have got tired of scrambling about under the truck so if anyone has experience of this I'd be grateful to hear from you.

I do have a handbook (in German) with wiring diagrams but for the life of me can't find these two!!!

[Aidan]

diff lock warning switch ?

[Al Housman]

Possibly Aidan but I have tried and I don't think it will stretch unless I have it routed the wrong way around the chassis (which is possible).

The colour codes of both sets of wires don't appear anywhere on the  wiring diagrams which would possibly indicate syncro specific.
 

[Al Housman]

So.....according to the Samba the blue/brown is the difflock switch. Which leaves me with the brown/black to fathom out.

[Aidan]

does it come out of the loom adjacent to the reverse switch and fuel sender wiring, same type of two pin plug with rubber boot ?
If so it is the decoupler wiring which is in the loom and usually folded up under the loom by the chassis leg and cable tied in place
Syncrosport has iirc the full Syncro wiring for difflock and decoupler , sorry it's not in Bentley

[Al Housman]

Thank you Aidan. I reckon you've hit the nail on the head there. it's sort of kinked a couple of times which would probably indicate that it's been folded up out of the way for some time. There' s nowhere close by for it to go to!!
Cheers. I can stop scrathing my head.