Alternator wiring

[Laaf]

Hello, I have a wire to my alternator which doesn't belong to the standard loom for it. The standard loom has the 2x red wires for 12V+ to 30 in the fuse box, and the blue wire for the dash. Then I have got a wire going for the last connector on the back of the alternator, a spade connector. I havent turned my head around the engine compartment to see if there is a marking beside this spade telling it's name, but I can supply a old picture from when I pulled the engine last year.



I am digging around in the loom anyhow, so I can measure and find out where it is, but I have no idea what function it fills as of now.

[S2central.net]

Strange - dunno wtf that is. Was that an OE alternator or some aftermarket / refurb item that has been modified for 20VT installation ?

[Laaf]

I think it might be the alternator belonging to the 10V original engine for my 4000. Anyhow, I have got VAG electric diagrams folder for the 90 quattro and this wire or terminal isn't mentioned there either. Just the two red to 30 and the blue to the dash.

[quattro-nick]

is there a "W" on the connection?

[S2central.net]

Will try to find some old old diagrams then.

[Laaf]

is there a "W" on the connection?

Might be, I can take a closer look tomorrow. But it is the only connector except + and D+.

[quattro-nick]

"w" connection is usually used for a tachometer in older diesel cars like golf mk2

[quattro-nick]

you only need to connect the red and blue wire to let the alternator work

[Laaf]

Yes I know. But I thought it be good to ask get a direction on where to search for the other end of the wire.
Looking at this post from the previous owners project thread it might just be an attempt on getting the tacho working. http://www.s2forum.com/forum/showpos...8&postcount=23
Well, going anyhow to look into it to be sure what purpose it fills.

[S2central.net]

I have found one old schematic showing an extra "W" terminal but no wire is shown nor a clue what it might be for.

[S2central.net]

It's a speed sensor that must have been used for some old cars -

http://www.boschautoparts.com/documents/11100/0/0/c2070f45-63d8-4414-855d-d216379ea0a5

[Laaf]

I had a look today when being at the garage and the connector had a "+" right next to it, but a bit on the side was also the "W" but that wasn't near any other connector either. So it is most probably the "W" then, but I haven't traced it back to the drivers footwell yet to figure out where it goes.

Well, found the other end of the wire, and it dead ended in a connector behind the dash. In the connector was another wire, a black 2,5. It changes color to green/black 1,0 to pin 3 in the connector for the voltage and oil temp meters.