Now that the engine is running I need to finalize some of the electrical connections. Notably, the alternator is near the top of the list.

Normally a regulated alternator has 5 connections

12V to battery
D+
D-
Df
GND

The Suby alternator is internally regulated so this elminates the Df wire.

I need to connect up the D+ and D- to complete the voltage comparator.

It looks like the blue D+ wire goes to Pin1 and I send 12V to Pin2 on the alternator. 12V becomes the effective D- wire to complete the circuit on Pin2. Basically, the current across the dash bulb that is a result of a difference in voltage between the alternator and the battery regulates the charge. At least, that is how I understand the wiring.

Any thoughts?

From the subaru factory manual......
Click to view attachment

Bob

Thanks Bob but that is a much newer alternator than the 97 that is in my car. I only have a battery post/terminal and a single 2-pin plug connector.

Not a Subie but... On my rotary conversion I ditched the Mazda Alt in favor of a Chevy 1 wire. I did use a 175 amp Power Master but you can get a 80 chevy at your FLAPS cheap. Makes the conversion easier than using the original parts.

Here is a cut/paste from the 1998 Subaru Outback factory manual. Hope this helps...

Click to view attachment

Just walked out in my garage and looked at my wiring harness from my 1994 Suby Legacy Turbo that I've adapted to my 914 harness. I matched the wires to the wiring diagram in my Chilton manual, and confirmed them in my electronic version of the factory manual.

My connections to the alternator are as follows:

1. Large gauge white wires on ring connector (to fusible link)

2. Round black plug with three wires:

a. White wire (to fusible link)
b. Yellow wire (to fuse #16)
c. Black/red wire (to charge indicator on dash).

What year and model did you engine come from?

Geoff

Geoff,

Thank you for the listing. The engine is from a 1998 JDM GC8 Turbo (Forester). I can only find an Impreza wiring diagram. The connections are the same but the colors are very different.

I only have a 2-pin connector and a lug terminal on the alternator. I think your post confirms that I connect the dash light wire directly to the alternator and the other pin directly to the battery.

here is the Subaru Factory diagram I am working from.



The connection [ALT-1] goes directly to the dash charge indicator light. It would be same as the exciter current lamp on the 914 dash light.