4-wire alternator wiring question...

[nikwho]

So, recently had my new 383 built. While I was swapping the engine, I also changed my front accessory drive setup. I believe that it's out of an '89 Blazer, FWIW. It's the serpentine setup. Ill attach photos. My '59 Apache is re-wired with a Rebel Wire harness. If I have any questions after asking here, I'll just call Rebel Wire, as he has always been great answering questions, back when I was wiring the truck!

So, new setup has the 4 wire alternator. I bought a new wire plug/pigtail with four wires.. Previously, I for some reason had my alternator power and exciter wires (red and white wires) connected together. So, per what I found online, I put a ring terminal on the "S" (sensor) wire and looped it right back to the battery terminal on the alternator. I have yet to ground my alternator, but will be. In a "let's see if this works" moment, I took my power & exciter wires that were previously connected together in a 1/4" F blade connector, and crimped a 1/4" M connector onto the pigtail from the "L" terminal on the alternator.
In order from top to bottom, the terminals on the 4 wire alternator are "P, L, F, S". So, sensor (S) looped back to battery, and my wire harness power and exciter wires are hooked to the "L" terminal. Once I connected those wires to my "L" terminal, I checked my volt gauge and it had gone from 12v (not charging), to approx 13.5v (charging). However, it was making a whistling type of sound. I assumed that it was a bad bearing, perhaps, or something else not happy in the alternator. So, after shutting the truck down, I just started it back up and the alternator will no longer charge. I realize now that I've read about guys frying these 4 wire alternators, by wiring them incorrectly. I'm assuming that's what I did. Not super upset about it, as the alternator is an unknown unit to me, and I'm okay with replacing it with a new unit. BUT, I really don't want to burn up a new one. Can anyone offer a little wiring advice, to help me be a bit more successful here?

Thanks so much!

Nik

[dmjlambert]

Please post pictures of the front and back of your alternator so we know what you have.
Here's a thread with lot of discussion about different alternators and wiring them.
http://67-72chevytrucks.com/vboard/s...d.php?t=763180
And here is what American Auto Wire says about wiring the CS series alternators, which is probably what you have.
https://www.americanautowire.com/PDF...20IN%203.0.pdf
I will guess you probably didn't have enough resistance in the lamp wire. Normally this would be the brown wire from the cab. It has sufficient resistance to use to excite the older external regulator or 12SI or 10SI v-belt alternators. But for the CS alternators you add resistance between 35 ohms (5-Watt resistor) and 500 ohms (0.5 Watt resistor). Since the 500 ohm resistor can be much lower wattage and is therefore small and runs cooler, I think it is the best choice. In my case when I put a CS alternator in my truck I used an adapter pigtail that has just the S and L wires going to the alternator connector. The resistor is on the L wire, built-in to the adapter. It is a little more resistance than AAW mentions, 511 ohms. I went this way so I could get the alternator connector and resistor in one purchase, and I figured AC Delco and GM probably know what resistance is needed for alternators with that type of connector, so it gave me a little more confidence. On my truck, the S wire is connected to the main hot wire that goes from the battery to the cab, but it is connected at the junction near the driver side headlight, so it is a little distance from the alternator, not just a couple inches of wire to the terminal lug on the alternator. Connecting it downstream a ways is supposed to give the alternator's regulator a better sense of the voltage in the wiring harness so it can better regulate. The pigtail/adapter I used was same part number as driller35 used in that thread I mentioned earlier.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[nikwho]

Sorry. I meant to include photos. Ill have to wait until tomorrow now to grab a photo if the back of the alternator. I'll post a couple that I have now, in case they help. Also attached the diagram that I was referring to in first post.

Nik

[nikwho]

I do have another question, pertinent to this topic. I'd like to buy a new alternator. Will I be able to buy a simple (perhaps one or two wire) aftermarket alternator that will bolt in place of this alternator, and accept the serpentine pulley, that will be simpler to wire?

[VetteVet]

Nice rig you have their Nikwho.
You should take your alternator to any Autozone and have them test it for you. If it's bad I would upgrade to a CS 144 because it cools better and it has a little more output.
You don't need a separate ground because the alternator grounds itself through it's mounting bracket. You can get one through Summit Racing or Jegs or just about any of the aftermarket suppliers.

Wiring it up is simple as DJLambert has explained. You just need the L and S wiring terminals and a resister ( 35 to 500 ohms) wired in series with the L wire.

You may have damaged the alternator when you wired the L terminal with a hot circuit wire. If it was key on hot then you may be OK but you would still need the resistor.
Your rebel harness should have a designated, key on, hot wire for the L terminal unless you got a stock harness from them. They should have sent a schematic or a wiring diagram with it.

Your 59 was wired stock with the power wires going straight through the Amp meter and GM deleted that setup in 1963 with the new style ammeter (battery gauge)and then in 1974 with the voltmeter. Your harness should be adapted to fit one of those, hopefully it is the voltmeter style.

Refer to the thread that DJ posted above and all your questions should be answered.

[dmjlambert]

I agree, you're almost there.

Your Suzuki diagram has 2 interesting things. I think it is showing the resistor, and I think "to charge indicator" means it is going through an indicator circuit on the dash, which is probably a light bulb that glows to indicate a problem. That wire is not going to a plain 12V from the ignition switch. On the alternator, the L terminal means "lamp". Adding a resistor is what will enable it to work on a vehicle that does not have the indicator light.

[nikwho]

Ive got a voltmeter. Its an Autometer gauge, not factory gauges. Yes, I have the full Rebel Wire installation guide. Ill attach a screenshot of the page that speaks to GM alternators. Sounds like adding a light is just as easy as adding a resistor, then. I have a spot on my aftermarket gauge panel that I could stick a light, then, if I'm not mistaken, the light will illuminate when the system is NOT charging, correct? So, light on with key on, light off when running/charging, and light off if something causes the system to stop charging?

Thanks much,
Nik

[dmjlambert]

Yes, the light indicates it is not charging or it is overcharging. It should be a conventional incandescent bulb, not LED bulb. As I understand it you should still have a resistor in line, and should also have a resistor in parallel with the bulb. If you just have the bulb and it burns out, your alternator will stop charging. With key on and engine not started yet, or during start when the RPM is low, the light will glow as a bulb check.

[nikwho]

Didn't know about the over charging thing, and hadn't thought about the issue of not charging if the bulb burns out! Sure wish Radio Shack was still a thing here (are they open anywhere, any more?). I'd be a lot easier to run to Radio Shack and buy the resistor that I need.

[nikwho]

So, still being confused here, will I even use the "exciter" wire from harness? Or only the red "alternator power" wire?

Nik

[dmjlambert]

Yes, exciter wire goes through a resistor to the alternator L terminal.

[nikwho]

Got it! Thank you! I've got it hooked up like that now. No light when key is in "off" position. Light is coming on when key is in "On" position. Light dims as I crank and goes out as the engine fires! Unfortunately, its no longer charging, though. Sits steadily at 12v while running. I'm thinking that in my "lets see if this works" moment, I probably fried it. Though, im not too upset about it. It seems as though I now have it wired correctly, and I should be ready for a new alternator.

If I upgrade to the CS 144 alternator, as VetteVet recommended, will it use the same pigtail as my current alternatpr? Also, what application (year/make/model/engine) do I ask for an alternator for, when I go to NAPA?

Thanks again!

Nik

[dmjlambert]

Yeah, no more Radio Shack. You may have an electronics parts supplier of some sort in your town, otherwise you would have to order online. Buying a pack of resistors would be a little less expensive, but I ended up ordering the pigtail/adapter that already comes with a resistor so I wouldn't have to go on a hunt.

[dmjlambert]

The one I ordered was for 1993 C1500 Cheyenne trucks, Optional Heavy Duty 124 Amp. I ordered the store brand lifetime warranty alternator at O'Reilly Auto Parts. When it came in I made sure it had Delco Remy and USA stamped in the case, because I was going to say no-go if it did not. I know some of the insides may be foreign since it was a rebuilt one, but having the case stamped like that gave me a better vibe. I don't know if it would work with your brackets and serpentine belt system, mine is plain V-belt.

If you only have a light bulb so far, I'm not sure that is enough resistance to keep from frying it. It seems like the light is not doing it's job if it's supposed to tell you there's something wrong (not charging). So I would never mind the light idea and go with a resistor.

[nikwho]

Well, everything that I have read indicates that the resistor is just to function as a back up, in case the light bulb burns out. I'm going to install one, but it seems as though it isn't necessary for proper function of the alternator. I REALLY wonder if there are simpler 1/2/3 wire alternators that would bolt in place of this alternator, and accept the serpentine pulley. I'd greatly prefer that, over soldering resistors, and having such headaches. Just seems that with this system, there is a higher chance of failure on the side of the road for some silly reason. Seems as though I've got it wired correctly now, though it also seems as though my alternator is fried! (Another reason I would just as soon run a different type of alternator).

As a side note, when I hooked it up incorrectly, it began charging, but made a high pitch noise, like a bad bearing. Now, when the battery cable is connected to it, it makes a very quiet humming/whirring noise. So, I fried something. Im sure that if I install the same type of alternator, it would work well, and I wouldn't have to think about it for years. However, I'm just not a big fan of these so far, and from my little bit of research, they're quite a bit more expensive than the alternators that I've run in the past.

[dmjlambert]

The more modern the car, the fancier and more expensive the accessories. You took the plunge when you upgraded to the serpentine belt and bracket system with accessories. I sure would like to do that.
I think once you get the resistor in the circuit and get things going you will probably love the alternator. When I looked at the tons of "help I just fried my CS130 alternator" posts on the internet, especially in all the Camaro forums, my perception of the research others have done very often boils down to GM used a 510 ohm 1/2 Watt resistor on the L wire in the various adapters or pigtails GM sells for $20 to $40.
If I were in your shoes I believe I would get parts to match the 89 Blazer because that is where the serpentine belt and bracket system came from.
I first upgraded to a cheap Chinese 12SI alternator, which is a V-belt alternator, and it only lasted a year. Then I did lots of research and decided to take the plunge and get a CS144, which is very modern and came with a serpentine pulley installed, but still somewhat compatible with my V-belt bracket and pulley. I had to file the top adjuster bracket to make the groove a little wider.
I still have all my original wiring, and used adapters to wire the alternator. At some point I will probably unwrap the factory wiring harness and replace some of the wires and solder and shrink wrap the resistor directly into the harness so I don't use adapters any more.
I believe I've paid for the last alternator this truck will need me to pay for, because I got a lifetime warranty one from O'Reilly. Unless I do a serpentine belt system swap like you did, then I'll be back to no warranty and good to go for as long as the donor alternator works.

[nikwho]

Good points there! I'll suck it up and replace the expensive alternator. After all, the work is done now. A new alternator will be plug and play! I ordered the resistor, too, so it won't stop charging if my dummy light burns out. Once this is done, Ill be able to focus on getting air conditioning in the truck. Want to be comfortable for the drive to Dino's Git Down this November!

[VetteVet]

If your alternator checks out as bad, and You feel up to it, there is a You Tube posting on how to repair the CS alternators that is very good,and it would save you quite a bit over buying a new alternator.I'll see if I can find it. It looks pretty simple to me.

https://www.youtube.com/watch?v=dFuW...re=emb_rel_end

[nikwho]

So, I have officially fried my SECOND CS130 alternator, trying to get this all to work, and its getting expensive, and very frustrating. LOL... I would greatly appreciate any help on getting this third alternator wired in a manner that will keep it from cooking itself.

I have read up on wirimg these alternators, and thought that I had it figured out. I bought a new alternator from NAPA, and hooked it up according to the picture that is attached to this post. I ran my battery + wire to the battery terminal of the alternator and looped the "S" wire from the alternator around to the same battery terminal. Then, in lieu of a dash indicator bulb or the aforementioned resistor, I ran the wire from the "L" terminal to a light housing that I had that held an 1124 incandescent light bulb in it. I ran the "L" terminal wire to the ground side of the housing and ran the white 14ga. Alternator exciter wire (in my Rebel wire harness) to the positive side of the light housing. I also grounded the alternator, to ensure that it had a good ground. I figured that the load of the light bulb would offer enough resistance to keep the voltage regulator happy.

Here is the light housing that I used in lieu of the dash indicator bulb. I used this in an effort to offer resistance, while I was waiting on a resistor that I ordered to show up.

https://www.etrailer.com/Trailer-Lig...on/433600.html

So, from what I have read, this is an acceptable way to wire a CS130 alternator. I drove the truck for two days like this, running an errand or two each day. The truck was charging at about 14.6v on each trip, and all seemed well. Then, on the third day, the alternator stopped charging, and that damned light bulb illuminated while the truck was running!

Here is the new alternator harness that I bought, that has the resistor pre wired into it:
https://www.summitracing.com/parts/ado-pt2145?filters=

I like to think that I am a fairly intelligent person, with basic electrical understanding. However, after frying this second alternator, I am getting a little "gun shy" regarding wiring the third one!

I am in need of some help, figuring out how this danged thing needs to be wired! I am getting tired of buying alternators! I also have an email into Rebel Wire, which is the maker of my wire harness. I have been nothing but pleased with my Rebel harness, and they have been extremely helpful any time that I needed help while wiring the truck. I am attaching the wiring diagram for CS series alternators that Rebel Wire sent to me. I am a little confused, looking at their diagram. Seems like a lot is going on here. Definitely more than what I have read needs to be done with these alternators elsewhere. And, the harness that I bought claims to make the alternator a "two wire" ordeal.

Thanks so much!

Nik

[nikwho]

My lack of clarity resides here, with the wiring of the "L" terminal.

[nikwho]

Firstly, the wire that intersects this "L" circuit, from the ignition switch, with the fuse inline; is this the "Alternator Exciter" wire from my wire harness?

Second, shall I cut up my new alternator wire adapter, to tie in a dash indicator light, wired across the resistor?

Third, that new adapter that I ordered only has two wires (L & S terminals). Yet, this diagram shows all four terminals being used! I assume that the "P" terminal does not need to be wired to a relay or tachometer.

Fourth, this diagram appears to have each side of the dash indicator light and resistor wired across terminals L & I, but also shows this circuit between L & I also tapped into by the fused wire from the ignition switch, that I assume to be my "alternator exciter" wire. Im sure that I am over complicating it in my head.

My plan was to take the two wires from the new adapter harness, with the built in resistor, and loop the wire from the S terminal back to the battery post, and hook the wire from the L terminal (with the resistor wired inline) to my alternator exciter wire, from my trucks wire harness. HOWEVER, I have previously made assumptions with wiring this alternator, that have proved to be expensive.

Thoughts, comments, concerns? Scintillating (or derogatory) statements?

Any help will be greatly appreciated!

Nik

[dmjlambert]

Sorry to hear about those troubles. I think perhaps that light offered too little resistance. It is a bright bulb to light up the cab via a dome light, compared to an indicator light which is not that bright. If it were me, I'd not use a light and use that resistor adapter you bought, and not connect the I terminal. Just connect the S and L terminals of the plug. The L terminal goes through the resistor and then to a source of switched power. That would normally be the brown wire on a stock wiring harness. I don't know about the Rebel harness white exciter wire.

Here is why I would not use any terminal on that plug other than S and L. PLIS type regulators use the I terminal as an input, and PLFS type regulators use the F terminal as an output. F and I are in the same plug position. The stamping on the case of the letter F or I does not necessarily guarantee the regulator that matches the case stamp is installed inside that alternator. Some alternators have that terminal marked F/I. You can't identify or trust what type of regulator you have in the alternator from the outside of the alternator. This is because unless you know the application (year, make, model, engine) the alternator was designed for, and trust your alternator supplier gave you the exact and correct alternator for that application, and you have the opportunity to walk up to and examine that newer model vehicle and see how that terminal is used in that vehicle by tearing into the wiring or researching the wiring diagrams (if available) for that vehicle, you can't trust whether that position is F or I. So, in my opinion, there's a 50/50 chance to fry a CS alternator by connecting the I terminal (it may be an F terminal and you don't know it and you may be hooking it up wrong). This is described in better language probably, but also much more brief, in the American Auto Wire article I gave the link to earlier in this thread.

Here is the reason I would not use a bulb instead of resistor: In my observations by reading threads on this forum, I have developed the impression in my head that gauge clusters are far more common than idiot light instrument clusters. I don't know that for sure, and perhaps the folks with idiot light instrument clusters just happen to be more quiet or don't do as many customizations in the alternator area. Or perhaps they are super smart and just do it right the first time and we don't hear from them much because they're not posting about their problems. I'm assuming gauge clusters are more common, and the total accumulated experience on the forum leans toward doing alternator upgrades to later models such as SI and CS alternators in trucks that have gauge clusters. I want to stick with the crowd. I have not seen any threads on this forum about upgrading to CS style alternators on a truck with an idiot light instrument cluster. And finally, I don't know what bulb number to use, I'd have to research that by finding out what application the alternator was designed for, and researching the wiring on that newer model vehicle to see what idiot light bulb it uses, and further research to find out whether any resistors or resistance wire is used in series with that bulb. Just too much to research. I'd rather wait for one of those brilliant idiot light instrument cluster guys chimes in here to say "this is how I did it with my idiot light instrument cluster, here's the parts you'll need and the wiring diagram, and I've had it installed and working well in my daily driver for 5 years."

I wrote too much! It must be caffeine or cabin fever...

[dmjlambert]

I am wary about that diagram from Rebel showing CS alternator hookup, because they don't mention the possibility of the I terminal perhaps actually being and F terminal, depending on what "application" your alternator is for. Who hand wrote the "F" on that sheet next to the I? There are no hand written notes what the F is all about...

[nikwho]

LOTS of good information dmjlambert! Thank you very much! I just went back and looked at your link earlier in the thread again. Interesting that the American Autowire write up that you linked states that only the "L" terminal is used, and it makes no mention of hooking the "S" terminal wire to anything!

[nikwho]

Regarding where to hook up the "S" terminal wire, I really wonder how much difference of a reading it can get through 3" of 10 ga. wire, vs. 2-3' of 10 ga. wire. I couldn't imagine the voltage reading being any different. But, my assumptions have already cost me a few hundred dollars, regarding how this alternator should be wired!