Ok, no sooner than I laud the local generator shop, an 11 month old reman suddenly quit charging. 88 cs130 in a GT.

Voltage light will not turn on, I have tried changing the bulb as well as the bulb socket with a known good socket and bulb to no avail.

Fusible link for the alternator from the power distribution block "appears" undamaged, 12v triggers a test light at alternator pigtail at outer two terminals with the key on (a spliced in aftermarket 3 wire connector here). Nothing from the center wire.

All fuses test good.

Now what? Is there an alternator component failure that will kill the voltage light?

I basically am just looking for a suggestion on wether or not to simply pull the alternator for a warranty exchange at this point, or if I should be digging into this "brown wire" that ties into the voltage light. I haven't the faintest idea where to trace it, if so.

It's been a rough couple of weeks at work, so forgive my less than thorough approach. I did some forum searches and haven't found much conclusive.

I think I'll go explore the cave in the meantime. Any pointers would be much appreciated!

GT still uses bat idiot light on dash to turn on I think. Don't have my car data this week.

Most times the CS alt regulator can die. More so no-name re-builders often w/ cheapest parts they get.

jump lamp wire on alt side plug with a test light to see if alt turns on after a few seconds w/ engine running.
take alt out and test at most any local parts store.

If bought online, worse ebay/amazon, then good luck trying warranty claim. Even honors that can take days or more to get a new alt.

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quote Originally posted by viperine: Ok, no sooner than I laud the local generator shop, an 11 month old reman suddenly quit charging. 88 cs130 in a GT.

A local shop where you got it?
I'd take the alternator in to them and have them test it.
It's the quickest/easiest solution to do first.
You could spend hours tracing a "wiring problem" that doesn't exist.



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[This message has been edited by fierosound (edited 07-12-2018).]

So, the CS130 shouldn't *need* an idiot light to start charging - it should eventually self-energize... running the engine up to 1500 or 2000rpm should be enough to get it going. If it doesn't, there is probably something wrong with the alternator. I am not familiar with the '88's wiring, but in general:

There are four terminals on the back (and they will be labeled), PLFS plus the big B+ battery terminal. I actually don't know how the '88s are wired, but the idea is that "S" is how the alternator controls its charging, so it either gets connected directly to the B+ terminal (how us DIY retrofit hacks do it) or it will be connected further upstream to the car's wiring harness (how the factory does it, for better charge management). At that point, with a couple thousand revs on the motor, it should start charging by itself. So, you can test for battery voltage at both S and B+ with the car off to be sure those pieces are in place.

The idiot light is there for us and so that the alternator starts charging immediately. It's connected to terminal L on the alternator. With the engine stopped, you should have a ground on that terminal. With the engine running, you should get alternator voltage once the alternator starts charging. You can quick & dirty simulate the lamp by getting a 35-500w 5w (or greater) resistor and bridging L directly to the battery terminal. It'll kill your battery if you leave it this way, but for testing purposes it's an easy way to rule out the idiot light wiring.

I think on the Fiero P is not used, but the I terminal I believe will be connected, and connected to a switched ignition source. You should get 12v here with the car on, but the engine off.

That's all the testing you can really do... test those three terminals. If they all check out, it's the alternator.

Some great details here, guys. Thank you all! I will get to testing tonight after dinner. Some advice from my mechanic and the generator shop both this morning goes hand in hand with the responses as well. Even at this point, they lean towards an alternator failure. Generator shop offered to build me a self-exciting alternator as well, if I don't mind giving up the voltage light.

I don't remember what the reason is, but I think "single wire" alternators are generally frowned on. The factory idiot light system works very well and gives you a heads up if things go wrong. I'd think losing that system a detriment. *Assuming* your idiot light circuit is good (which you can tell easily by grounding the "L" terminal of the alternator - with the key on, the light should light) I'd look to get a good/correct alternator in there. At least the CS alternators are super easy to get in & out!

Got the alternator pulled last night, dropped it off at the generator shop this morning, picked up the replacement on lunch break, and just installed it an hour ago along with dodgerunner's tensioner bracket. Now I just need the correct belt, I ordered two gatorbacks of the correct part number and received belts 2 inches longer. Not sure how I missed that, but I had the tensioner kit and had ordered the belts via ebay more than a few months ago. What a rip from eBay! (If anyone needs a 5 rib 47 inch belt, let me know! )

As for the final cause of failure, it was the voltage regulator. So much for relying on the voltage light!

Pretty sure they handed me the correct alternator, and not a self-exciting one as mentioned above. I was in too much of a hurry to return to work. Will find out once the correct belts arrive.

Big shout out to dodgerunner for a well designed, and thoughtful piece of work in his tensioner bracket! It really fits perfectly!