The alternator produces 55 amps with an internal regulator. It's an AC Delco #335-1271, Wiring harness is a Rebel Wire 16 circuit. The exciter wire is hard-wired to the fuse box. There's a voltmeter on the dash, but no idiot light. I know the alternator's stud (B terminal) is connected to the battery & starter with a thick (10 ga) red wire. The alternator isn't a 1-wire, so it's not self-exciting and therefore, it must have the exciter wire connected, but to which of the other three (IG, S/G, L) terminals? I- Is this connected to the exciter wire? S/G: This enables the alternator's internal regulator to read actual battery voltage, right? Where would you connect it? L: Is this unused, since there's no warning light? Photos: As always, thanks, guys.
looks like you'd call I the exciter wire. The one that goes to the ignition switch. Connect the G battery sense wire to the big output terminal. Leave the light wire disconnected.
Squirrel; With the I wire going to the ign switch would you want it on the Acc side or install a directional diode to keep from having run on after turning the switch off or would the internal reg do that job?
I don't know if this alternator back feeds through that wire. The older 3 wire alternators, which combine the exciter and light circuits, sometimes need a diode or resistor to prevent this problem. But since this has separate wires, I doubt it's an issue.
Squirrel, Shouldn't the G (also labeled "S" on some diagrams) go to the battery (or close to it, like maybe the starter solenoid "B" post) to sense actual battery voltage? Pist-n-Broke, my exciter wire is hard-wired into the fuse panel, so I don't have a choice what the other end connects to. Not trying to be argumentative, fellas. Just trying to get my mechanical head around this electrical black magic and really appreciate your input.
This was an interesting post in that I received an Alt like the one you have in question with the 40 Truck out of my Brother's estate and had no clue what it was from. Didn't matter, it's Chromed and looks to be new so I set it aside. Should the time come to use it at least I have some insight on how to wire it up.
Yeah, you should connect it to the battery itself. But hardly anyone does, and they seem to work just fine....
Damn the instructions can't get much simpler. L is the exciter wire aka to the idiot light. No idiot light you need a diode in the line. I goes to the switched ignition. G goes to hot all the time. B goes to the battery. I think the confusing part is that the diagram on the bottom is labled S for sensor rather than G as it is above. Plus the plug is upside down in that image compared to the other one. If you aren't sure what pin the red, green, blue wires go to get out ohm meter and check them.
Actually, that wire is there to help reduce voltage drop in the harness under high load conditions, so it's supposed to be connected upstream from the alternator/battery. It's usually factory connected to a unswitched 12V source at the fuse panel. The idea is if there's a drop at the panel, the regulator will sense that and increase voltage to reduce or eliminate the drop. In other words, if the regulator is calling for 13.8V but you only have 13V at the panel because of drop, the sense wire will tell the regulator that and it will increase voltage to reduce the drop at the panel. This is how the factories wire these. Connecting that wire to the output terminal on the alternator or at the battery is basically converting your alternator to a one-wire and you lose that function.
This alternator is original equipment on Suzuki Samurais. Its popular due to its small size. True. Unfortunately Jason, their tech support guru, no longer works there. True, but nothing specified "exciter" and that left me in doubt. I figured a HAMB thread would remove any uncertainty.
So I could connect it to any unswitched 12-volt source, like my unused "Radio Constant Power" wire (which normally would power the clock inside the radio, if I had a radio) ?
That alternator works a bit different than most do. It needs switched power to turn the regulator on along with the exciter wire to get it to decide to charge.
Here's rest of the story. The little Nippondenso alternator/ Rebel Wire harness combo works well. Here's how they're connected: I confirmed the battery was fully charged to 12.75 v, then fired up the engine. The voltmeter on the dash read 12 v for about 2-3 seconds then jumped to 14 and stayed there. I assume that was the exciter activating the voltage regulator. After connecting the wires with the light bulb, I removed it and still got the same results, so left the bulb off.
I use same Alt , No 3 wire hook up , For me thoe , @ start up , fast idle around 1,300ish cold start ,Then ramps down on Rpm's
Even though I have a voltmeter I like having the warning light too. It's reassuring watching it go out when the engine fires up. Or maybe it's a throwback to my start in cars, 60's British cars, where the charge light was called Ign, for ignition. Chris
Thank you Just Gary as well as squirrel for your post and input. What's more Old School than using parts you already have on the shelf instead of stepping up to the parts counter and spending $$$? Also, there are times when size does matter and Smaller is better than bigger. These help posts are exactly why I keep coming to the HAMB. Comments like this just make me shake my head and wonder why.
As a brief aside/ addendum, if you like shiney, these little Denso babies shine up nicely. The casting requires minimal casting flash removal, skotchbrite on a die grinder and off to the buffing machine. The plated rear cover goes straight to the buffing machine! The pic is a work in progress and isn't perfect and I don't know how the polish on the cover will last in use, but hey, it's literally free! Chris
There are a few 50ish 60ish 70ish 100ish Rang $60-130ish There is 2 case sizes in mini & I think a 3rd, pic should be middle of mini Powermaster has other Denso sizes For reference
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