3 pin alternator wiring for ej25

[JasonPap2002]

Hey folks,

 

I have an ej25 out of a 1999 Forester in my 1984 Vanagon.  Runs great. Currently the alternator warning indicator lamp will not turn on. It hasn't worked since the conversion.  

 

 

One side of lamp is on ignition power, the other side goes directly to the alternator.  If ignition is on and I touch the other wire to ground (the side at the alternator), it lights up. However, if I touch the end to the "L" on the subaru alternator (pin1, closest to the B+) then it does not light.  L is not receiving 12 volts at this time but it's also not receiving ground - it's apparently open.

 

Try as I can I can't make the L have a ground, ever.  I've tried all combinations that I can think of.  I have pin 2 "S" in the connector wired directly to B+.   You can see the connector and two wires with B+ post to the right in this photo:

 

 

And the wiring that I found:

 

Here are the details:

• With ignition off: L is not ground, S is not ground. 
• With ignition on, but car not running: L is not ground, S is not ground. 
• With ignition on, car running but L without 12 volts (field not excited), alternator  puts out 13 v.  S is at 0 volts. 
• Once 12 volts is placed on L (say by touching the alternator warning lamp wire to it), the alternator puts out 15+ volts, and then S has .33 volts. 
   

My understanding is that with ignition on and alternator not spinning, then L should route to ground.  

If someone can confirm the actual wiring behavior they have I'd be much obliged. I'm almost starting to think it's something internal to the alternator but it appears to work fine otherwise.
 

Thanks folks!  I've learned a ton from this board.

Edited September 6, 2013 by JasonPap2002

[Gloyale]

L terminal should be ground when S recieves 12v alt not spinning (eng off)

 

Alt seems to be working but has fault on the L circuit.  Not grounding lamp and also spiking over 15 volts when excited means that the ALT has a problem in the voltage regulator inside.

[JasonPap2002]

L terminal should be ground when S recieves 12v alt not spinning (eng off)

 

Alt seems to be working but has fault on the L circuit.  Not grounding lamp and also spiking over 15 volts when excited means that the ALT has a problem in the voltage regulator inside.

 

Thanks!  I feel the same now, have done all sorts of tests this weekend.

 

Anyone have a recommendation as to the most cost effective place to buy a suby alternator?

 

Found on amazon $121 but not sure if I can go there.

[Mugs]

Pull and Save or equivalent in your area.