Where does the output wire go from the alternator?

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CovKid
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Re: Where does the output wire go from the alternator?

Post by CovKid »

This is a lot simpler than it sounds.

Thick wire from Alt, connector at starter, red wire up to black box, and battery positive are all one and the same. They all join up with one another no matter where they're routed. The red wire to black box can be taken from either the B+ on alternator or at starter, it doesn't matter, they are in effect all one connection:

Image

I suspect that the way its wired has as much to do with vehicle assembly at the factory as anything. When I replaced all my original charging/starting cable I wired it exactly as above, despite the way VW had routed it all. I just fitted an even thicker cable than stock between battery and starter (see WIKI link I posted earlier) and finally ran a feed up to black box in the engine bay, from starter connection.

This illustration is (as some will recognise) from the VW Beetle fitted with alternator but makes it easy to understand. The wire colour coding from bug to T25 has not changed and even now I keep a laminated copy of the later beetle diagram as it makes wire tracing a breeze on the T25 - good tip if you struggle with the Haynes version.
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Re: Where does the output wire go from the alternator?

Post by Shotage »

Thanks for all your help, I think we are now sorted, well kind of.

That 30amp draw was coming from the manifold heater and was causing a problem. It was on with ignition and if the van didn't start first time then it soon drained the battery. We have disconnected that now (for the time being) and it seems to be fine.

Thanks,
Andy
1988 VW T25 Auto Sleeper
1.9 petrol / watercooled

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Re: Where does the output wire go from the alternator?

Post by itchyfeet »

Ok so problem sorted for now but you may want that manufold heater in the winter if its as bad as they predict
:ok
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Re: Where does the output wire go from the alternator?

Post by Shotage »

One answer unearths another question! :-)
1988 VW T25 Auto Sleeper
1.9 petrol / watercooled

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itchyfeet
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Re: Where does the output wire go from the alternator?

Post by itchyfeet »

As I said none of the engine electrics are fused
I have added fuses to the back box ignition and heater circuits, the alt and starter can't easily be fused so careful periodic inspection of the wires is required, any insulation breakdown needs urgent attention.
note the starter cable on a wbx is prone to rubbing through on the chassis rail add some extra insulation as in the pic...

Image

Image
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Re: Where does the output wire go from the alternator?

Post by Gixerman60 »

Hi
I know original post some years ago but battery stopped charging, van kept cutting out. Couldn't get alternator off as an oversized bolt had been forced through from the back ( any ideas on extracting this without removing engine ) . Replaced the brush box/regulator, fiddly having to do it blind by feel, but instant, and cheap fix.
Not sure where this belongs, but very disappointed with quality of parts from Just Kampers and customer service. Bought a sliding window to replaced leaking window app sliding door. Hole had to be enlarged, but fitted but my restorer. First heavy rain, leaks. Tested it, and drainage slots on outside too small to drain quickly so excess water gets under fixed glass and into van. JK refuse to do anything as they claim widow is only suitable for existing cutout ie mini bus. Not what website says. Also has to angle going section out of swivel seat base to access leisure battery. Wont even talk to me about that, say never had a complaint before. Spent hundreds with them, but no more. Does owning T25s make us suckers. Can we post about substandard parts and service?

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Re: Where does the output wire go from the alternator?

Post by Oldiebut goodie »

JK have been mentioned on the forum for many years about the quality of their parts. It pays to read the forum often.
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