its time to wire in an alternator on my ej swapped hatch.there two wires on the connector side that I am not sure of.A black with white tracer and a yellow wire.this is for a 91 3 wire alt.I imagine that one is hot whenever the key is on,and the other is the charge light.Going by subaru color coding yellow is normally a power so would it be safe to say that the yellow wire is switched hot,and the black wire with the white tracer is for the charge light?

 

my car started life as an 81 hatch with an externally regulated alt.Will the factory charge light wire in the harness work even with the regulator unplugged and thrown away or would I need to splice in a wire somewhere?

 

thanks in advance.

I think you are correct. The blk/wht lead is the lamp lead and comes from the warning light in the dash. Power from the ignition switch runs through that circuit to power the exciter inside the alternator. The yellow lead should be for the regulator voltage. It should tie to fused power from the battery but I'm not sure if it goes through the ignition switch also or direct.

 

Edit:

I was wrong with the above advice. I checked my manual and it shows the battery 'sense' lead is the blk/wht lead and ties from a fused wire from the battery to the 'S' lead of the alternator. The other 'lamp' lead or warning light lead is normally a wht/red wire color that ties to the warning lamp in the cluster and then to switched ignition power. The Yellow color wire is usually used for the wire between the minus side of the disty and to the tach in the cluster. Make sure that the yellow wire isn't that lead.

Edited May 13, 201213 yr by Cougar

the alternator wiring for the EJ alt has a yellow wire, a black wire and a large white wire.the white wire taps into the battery feed wire about 8" from the connector.

 

the alternator wiring on the 81 has the large white wire in addition to a solid yellow wire,a solid black wire, and either a white/black tracer or yellow with black tracer(the wire looks like a darkened white wire or a faded yellow wire with a black tracer.)

 

so what connects where?

on my 95 its a 2 wire alt..... the big thick wire is 12v pos. the other wire is the dash light....think its wht/blk but its super skinny.

 

i would find out which one is the charging light and hook it up to the "L" pin on the alt and wire up a 12v straight to battery and hook it up the the (s) pin and be done with it. should be a little pinout on the label of the alt.

What He said ^

Most of the ones I've seen have a label with the pinout. The larger of the two wires just goes to 12V. Some tap directly into the charge lead, later models it runs to the underhood fuse panel. Either way as long as it gets 12V while the key is ON.

Can't help so much with the EA wiring. I thought there was a swap write-up about this in the Old gen forum?

so I looked at my manual and BW goes to the charge light,the other side goes to fuse 15 on the legacy panel. The yellow wire from the alt goes directly to fuse 5 on the legacy panel.Also the actual diagram of where stuff goes says the BW gets power from ignition acc position,and the yellow wire gets power from ignition IG position.

 

So what wire is hooked up where?

This might help:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=129024

 

Explains the difference between 2-3 wire alts from the EJ's. I switched from a 3 wire alt to a 2 wire alt.

 

HTH!

got it hooked up i think. yellow was switched power and bw is charge light.my cheapo multimeter shows 13.5v across the battery terminals with it running so it must be doing something...

You should have near battery voltage on both of the wires when things are working normally, just like you saw.