Subaru Hitachi Alternator wiring...

silverbullet · Initiate Jedi Joined: 03 Sep 2009 Posts: 25

One from an infrequent visitor...I've returned to my "Microbru" project after a long absence and generally getting distracted by other wiring aggro on another bus. OK so this is a bit obscure but I hope that someone can help!

As part of my early EJ22 conversion wiring re-work (ancient TSR chopped loom) and having just changed the dash pod, I have just realized that it has never had a working alternator warning lamp (or possibly it has always been connected up wrong)

The Hitachi alternator has a round 4-pin connector and I think that from investigating the factory 1992 Legacy wiring diagrams (pdf download, very comprehensive!) that the warning lamp wire is the Black with a white tracer, from terminal L (one of the parallel pair in the plug)
There is also a yellow wire that has been connected to the VW blue wire that goes to the warning lamp. I think this is wrong as it appears to be another 12v output ?

Everything works OK but I don't want to short or blow the dash PCB for want of asking first...

Many thanks in advance Wink

Obonobo · Posted: Tue Jul 17, 2012 12:22 pm Post subject:

Looking into this myself, I found the same thing. It means that if you do not have the charge light hooked up, or if its broken, you still have a charging alternator. Pretty fool proof system!
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Greetings from Sietze
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Driving a '75 Bay with a EJ22 '93 and 091 6-rib box.

And it's a long time since it looked anything like this!

Kai · Posted: Tue Jul 17, 2012 9:26 pm Post subject:

I could be reading this all wrong, your yellow wire, my understanding is that one side of the alternator bulb is +12v, the other side goes to the alternator which is switching between +12v and earth.

+12v when it's charging and earth when it's not charging. There for it would be pretty easy to detect which wire is for the dash bulb out of the four in the plug.

So I can guess what connections you have in a four plug alternator connection. But what do you figure them to be.... Out of interest?
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Think......

Don't sleep and drive!!!

Joel · Posted: Sat Jul 21, 2012 2:19 am Post subject:

Heres how my 92 Legacy Alternator is wired up

Should be the same as yours.

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1974 1303 Germanlook Suba-Beetle
Subaru EJ254, BoostR 17", 4 Wheel discs, Topline suspension and A/C

silverbullet · Initiate Jedi Joined: 03 Sep 2009 Posts: 25

Thanks Joel, a picture is worth a thousand words!

Crystal clear, I'l combine it with this mod if it results in "constant warning lamp syndrome"

http://www.weidefamily.net/vanagon/Pending_Content/Engine_Conversion/14Alternator/VanagonAlternatorChargeLightFix.pdf