Alternator question.....

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HotWheelsBurban

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I pulled the alternator this morning and brushes are good,, battery connections seem good. I just finished driving it around and it now reads 13.9 on my multimeter (instead of 14.6+ on cold start) and the volt meter gauge has dropped. Seems as though when the alternator gets hot in the engine compartment it reduces the output.
On my 99 Burb 5.7, if the battery terminal bolts are 1/8 of a turn loose, the voltmeter reads at 11 or 12. Tighten the bolts, and the gauge reads at 14 where it usually is. Lights on or off. Not saying I entirely trust the 22 years old factory gauge, but good connections are hella important on these trucks! 1/4 turn loose, and it is slow to start. Everything is clean and in good shape as far as starter, battery, and alternator.
 

454cid

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You're correct on sealed from the back, I de-pinned my old CS130 plug and an AD244 plug from the front! The seals were just boots crimped on the wire, looked similar to this after removal:

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Mine is not an individual seal like that. It would seal all 4 pins, if that many were actually installed. I didn't poke at it, but I assumed it was something like epoxy.
 

alpinecrick

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GM pinouts for their alternator regulators are either P-L-I-S or P-L-F-S. If you only have one skinny wire on it, chances are it's brown and on the "L," terminal. If there isn't a wire on the terminal, it's not hooked up. No secrets in the plastic connector! :waytogo:

Now your other options. Your current alternator sounds like it's fine and charging. Although the gauge needle might be misleading, those are acceptable voltage ranges. If you wish to upgrade anyway...

If you want to upgrade to your CS144 (because, free!), you can either buy that adapter harness you mentioned earlier (easily reversible) or de-pin your rounded connector for the rectangular one. If you have a junkyard nearby, that would be the cheapest option for finding one of those rectangular plugs.

Last option that costs a bit more...If have an internal fan on your alternator and a rounded plug, you have a CS130D. Since it's a '96, you can drop in a 140 amp AD244 alternator and reuse your current connections and have more oomph at idle - no plug changes.


Good info, thanks!
I'm leaning towards the adapter harness that way I keep my original connector and can run either of the two styles of alternators in a pinch.

The thing is I can buy alternatorman's adapter cheaper than I can buy a gen-u-ine AC Delco rectangular connector. I don't know what brand the connectors on his adapter are but the word is he has mostly good parts.
 

alpinecrick

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On my 99 Burb 5.7, if the battery terminal bolts are 1/8 of a turn loose, the voltmeter reads at 11 or 12. Tighten the bolts, and the gauge reads at 14 where it usually is. Lights on or off. Not saying I entirely trust the 22 years old factory gauge, but good connections are hella important on these trucks! 1/4 turn loose, and it is slow to start. Everything is clean and in good shape as far as starter, battery, and alternator.

Now that you mention it, that is something I should check because I have "custom" length bolts that protrude so I can clip jumper cables on the terminals.
 

CrustyJunker

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Mine is not an individual seal like that. It would seal all 4 pins, if that many were actually installed. I didn't poke at it, but I assumed it was something like epoxy.


Was it something similar to this?

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My original CS130 plug looked similar to this if my memory serves me right...Except the boot on mine was orange. New style connector had the individual wire boots. Once I de-pinned my original connector, the whole boot popped out because the crimped end couldn't pass through easily.
 

CrustyJunker

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Good info, thanks!
I'm leaning towards the adapter harness that way I keep my original connector and can run either of the two styles of alternators in a pinch.

The thing is I can buy alternatorman's adapter cheaper than I can buy a gen-u-ine AC Delco rectangular connector. I don't know what brand the connectors on his adapter are but the word is he has mostly good parts.

I like that idea. $30 is a lot for a connector, but flexibility is always a nice luxury! Especially if you're going to keep your old alternator on the shelf in case of emergency.

There's no major juice running through that plug, so I'm sure it'll be trouble-free for years to come.
 

454cid

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Was it something similar to this?

You must be registered for see images attach


My original CS130 plug looked similar to this if my memory serves me right...Except the boot on mine was orange. New style connector had the individual wire boots. Once I de-pinned my original connector, the whole boot popped out because the crimped end couldn't pass through easily.

Yes, but with only one wire/hole/pin (middle small space). I'll have to check to see if the seal is bonded to the wire and plastic connector body.
 

VIKING_MECHANIC

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If you have confirmed that your voltage is 14+, then most likely it's your gauge. On my C1500, it hovers around 13 and except for fairly cold morning, never gets over 14. Also, similar to yours, mine will fluctuate with the turn signal and when my headlights are on it will drop a few marks as well.
 

98 Nitro

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If you have confirmed that your voltage is 14+, then most likely it's your gauge. On my C1500, it hovers around 13 and except for fairly cold morning, never gets over 14. Also, similar to yours, mine will fluctuate with the turn signal and when my headlights are on it will drop a few marks as well.

Same here on my 98's cluster when the headlights come on, the important thing is the multimeter shows battery and alternator are good.
 

VIKING_MECHANIC

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Same here on my 98's cluster when the headlights come on, the important thing is the multimeter shows battery and alternator are good.
I forgot to add, with the multimeter on mine the charge is usually 14.4 and doesn't change when I use headlights, turn signals, etc. But on the dash, the gauge always fluctuates. The engine temp doesn't get above 160, also leading me to the belief that the cluster isn't working correctly.
 
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