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Hi everyone
I am rebuilding my alternator. Took it apart and found some faults. 2 rectifier diodes separated from the heat sink and all tested good, so I tried solder them back with no luck. I'm going to buy a new rectifier. The other thing I noted is there was no resister wire on the regulator. From researching some have them and some don't. I'm trying to understand the purpose of it. Does it have something to do with the dash warning light or jumpstarting the alternator on startup? The warning light always took about 10seconds to go out after starting up. Though it might be from a week alternator. So, what rectifier should I get and should I put a resistor wire in while I'm there.
1982 corvette. I'm assuming it's the original 70-amp alternator. 1101 037 70A 3029 12V neg. Standard motor products list. D4, D9 and D16 for rectifiers.
Since I was a GM dealer parts guy for many years, I'm not quite sure what you mean by a resister wire on the regulator, as I recall never giving one to a tech for replacement. Perhaps a photo?
Also, here's a pretty good video regarding rebuilding a GM 10SI alternator.
Thank you for the quick reply. Sigforty I bought that kit. not bad for small money. It would be perfect if they included the rear bearing, but still a good kit. No problem. My local Autopart store has them.
Sunflower 1972. Thanks for the video going to watch it after my reply. The part I'm talking about is possibly called something else.
Last edited by Bubbagum; Jul 11, 2024 at 03:06 PM.
Reason: forgot photo
Thank you for the quick reply. Sigforty I bought that kit. not bad for small money. It would be perfect if they included the rear bearing, but still a good kit. No problem. My local Autopart store has them.
Sunflower 1972. Thanks for the video going to watch it after my reply. The part I'm talking about is possibly called something else.
According to the 53-82 Parts & Illustration Catalog that Resistor is same used in ALL 10si 76-82.
Its value is a 40ohm...
Disconnected it should read out 40ohms
GM #830478 or Standard Motor Products (SMP) RU-25...
Only problem with the SMP resistor is its made in China now...
I now recall that resistor in the alternator. I didn't see a lot of them because most of the GM cars that came into the service dept. had an idiot light for the alternator and not a gauge. (Pontiac store in 70's - 80"s) 10si/12si alternator, what is resistor for???
Very interesting. I have both the idiot light and the gauge. Would it harm to put the resistor in let's say the idiot light burns out or just better for startup. My light took a small bit to shut off. Do you think I'd benefit to put one in that didn't have one to begin with.
Very interesting. I have both the idiot light and the gauge. Would it harm to put the resistor in let's say the idiot light burns out or just better for startup. My light took a small bit to shut off. Do you think I'd benefit to put one in that didn't have one to begin with.
I'm afraid automotive electrical is not my strong suite. If your alternator is original to the car, I would just put it back together the way I found it. With new parts, of course.
Hi Sunflower 1972
Thank you so much for your help. I’m putting it back the way it was. New rectifier ordered and other parts. Looking up on other forums. They call it an exciter wire. The “idiot light” lights up when the ignition is turned on. If you take the time to check that it actually working, It supposed to provide resistance to jump start the alternator. If let say you wire it like a hotrod and didn’t have the light, the resistor in the alternator is supposed to activate or jumpstart it. I think years ago I might have heard the term exciter wire. That’s the way I’m interpreting it. Some people might differ. It’s so good to have people you on the forum to share information with us. Thanks to everyone who commented on my post.
Kevin
Hi Sunflower 1972
Thank you so much for your help. I’m putting it back the way it was. New rectifier ordered and other parts. Looking up on other forums. They call it an exciter wire. The “idiot light” lights up when the ignition is turned on. If you take the time to check that it actually working, It supposed to provide resistance to jump start the alternator. If let say you wire it like a hotrod and didn’t have the light, the resistor in the alternator is supposed to activate or jumpstart it. I think years ago I might have heard the term exciter wire. That’s the way I’m interpreting it. Some people might differ. It’s so good to have people you on the forum to share information with us. Thanks to everyone who commented on my post.
Kevin
Alternators rebuild question.
