alternator D+ wire mystery inline tube thingy

[chachi]

looking for the route of the coolant level sensor wires, i stumbled into the black junction box on the driver's side top of the engine. i found at least three unconnected wires, one of which i can't find a terminus for. in the picture below you can see two unconnected blue wires that are shrinked and then get combined under the shrink. a single blue wire comes out of that shrink then that gets shrinked with a red wire and goes to the alternator. so looks like the two blue wires go to the connector i'm holding which has an empty spade and a blue wire coming out the other side. but there is a grey/white wire with a connector that doesn't seem to have a mate. i *think* the junction box is represented in the diagrams (1990 and later) as the black box spanning pages 97.208 and 97.209 but i don't see a grey/white wire around that box. any help appreciated!

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'74 transporter panel
'91 vanagon carat NAHT

[MarkWard]

The blue wires under the heat shrink are likely not original. VW used copper wire almost exclusively and the strands do not appear to be copper colored. You will want to trace where they go to get an idea of where they need to be connected.
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[chachi]

ok, yeah they don't look original and what is going on under that shrink when they get combined. i dont know and im not sure i want to disturb what seems to be already a tenuous connection, but they go into the alternator. why? you tell me.

but that grey wire...? and can someone confirm that is the junction box represented on those pages?
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'74 transporter panel
'91 vanagon carat NAHT

[T3 Pilot]

Those blue wires should be insulated to avoid arcing. If they serve no purpose You ought to consider removing them.

The single grey/white wire Which terminates in the yellow connector is a vestige of a planned but never installed engine malfunction indicator system. The other end of that wire emerges near the fuse/relay panel at the drivers position.

You can see the schematic of the system in the 1988-1989 wiring diagram Bentley 97.123 current tracks 18-20. The 1990 diagram only shows the gray/white wire itself in track 18

You could use that wire for something like an oil pressure signal wire.......

Also use caution around the red wires attached to the stud in that box, behind your fingers in the first image, that is battery + (sounds like those blue wires are as well....)

Good luck Van brother....
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1988 Vanagon

The most important part in every vehicle is the nut behind the wheel......

[chachi]

thanks t3 pilot, that's a big help.

definitely some aftermarket shenanigans going on with the blue wires. there is some inline white tube on the alternator D+ wire as well as a black wire in that box. looks newish. is this some kind of electrical filter?:

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'74 transporter panel
'91 vanagon carat NAHT

[ZsZ]

Alternator exciter addon wire:
http://www.gowesty.com/product-details.php?v=&id=24031
It reduces the load on the D+ post, so the alternator excites faster.

Just re crimp the connectors with quality ones not with that crap that Gowesty use (or solder them), put into new shrink hose and done.
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Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008

[chachi]

thank you ZsZ, i knew somebody would recognize it. i soldered it back in.
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'74 transporter panel
'91 vanagon carat NAHT