Hey guys/ gals,

I've tried to do some digging and not sure if I'm just misunderstanding or just not finding what I'm looking for.

Carbed SBC in my 92 RS, I've deleted the ECU and all the wiring associated with it ( minus fuel pump and a few other wires from the C100)
I didn't save the alternator connector/ not finding a definite color combo for the plug.


This is the plug I have for my alternator, I've been told to run the larger wire either directly to battery, or the back post on the alternator. Some say I need an inline fuse.
But... Looking online I see guys talking about running one of the wires to switched 12v/ some saying not too.
Others saying above, then run the other to a dummy light and/or a resistor/ not too.

That paired with me running a Dakota Digital VHX-90C-CAM-C-B dash, I'm lost/ overthinking it. How should I wire it to just get it done with.

My QP 9" is finally installed, and I would love to button up the wiring so I can drive it around once all the MN salt is off the roads.

Thanks!

 

Based on wiring schematic for 1988 Firebird, the only schematic I have....

Working left --> right in your photo:

Alternator S (Sense) terminal.
Connect to RED wire in your harness (I think it is 12 AWG size). This Red wire goes to a fusible link attached to starter motor battery post.

Alternator I (Ignition) terminal.
Connect to GRN wire in your harness. This Green wire comes from a switched power source (C/H-FAN fuse).

Alternator L (Lamp) terminal.
Connect to BRN wire in your harness. This Brown wire comes from the warning indicator light bulb in the dash.

Alternator P (Phase) terminal.
Not connected. Leave blank.

 

I have 2 12(?) gauge wires coming from the C100. So, they should both have a fuse able link, and connect that wire to those two? If so, would a 20a work?
Iirc my battery is wired to my alternator, then alternator to battery, 2 different 4ga wires.
Car runs fine with a battery charger plugged in(haven't tried without it)
I'll have to look for the green and brown wires when I have time tomorrow.

I have 2 switched 12v sources that I am currently using for the fuel pump and my fans. I could probably just tie into one of those, if wiring differs on a 92.

 

I think you changed topics mid-thought? The 2 large Red wires going into C100 power almost the entire car. Leave those alone.

Regarding alternator S terminal, Think of S terminal as a voltage sensor that enhances operation of alternator. Connect it directly to battery B+ post or starter B+ post. This will allow the S terminal to take a measurement of voltage at battery and charge battery to correct voltage. Do not load share other circuits on the same wire as the S terminal (give it a dedicated wire).

 

Gotcha, I probably did switch topics mid thought. Sounds good though, I'll give it a shot this week. Thanks for the help!

 

Just FYI - I don't think the S terminal is required for alternator to operate. It is optional but a good thing to have for battery health. If you don't hook it up, then alternator will ignore the S terminal and will regulate charging voltage using internal voltage sensor.

Point is, I think the alternator should do something with or without S terminal attached.

 

@QwkTrip
hey, thanks again. Finally have time to dig into it. Got sick as hell, then tweaked my back 😂😂😂😂

Question for you, my plug goes S F L P
So F would be ignition and L would be lamp?

 

That's right. Some alternators have SFLP type voltage regulator, and some have SILP type voltage regulator. However the labels on the connector are generic and don't necessarily exactly match the type of alternator.

The '88 Firebird wiring schematic shows SFLP for the connector, but if you look real close at the schematic it show SILP inside the alternator.

I don't know if any of the 3rd gen cars ever had SFLP type alternator.

 

Most all Third Gens will have Originally had the "P L I S" Style Voltage Regulator within the Alternator.

 

SILP.... PLIS...

Ah, man, I was soooo close this time!