Alternator Upgrade

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85K10

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Hey guys I am installing a serpentine belt setup on my 85 Chevy with 305. I got the setup from a 91 Silverado and am working on the alternator. I know the plugs are different and am working on getting the adapter. My question for you guys is does my amp guage (FACTORY) have a indicator light in it or is it just a guage? Guess that matters when getting the adaper. The adapter comes with a resister in it if its just a guage and without resister if it is just the warning light or guage with warning light. Thanks for the help.
 

oneluckypops

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mine has both but my cluster is from a 91 burb, easiest way to tell is turn the key on and see if the bulb tst lights up. it will only stay on for about a second, otherwise pull the cluster and see if its circuited for it with the bulb in it.
 

bucket

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I was just recently talking to my dad about this topic, we came to the conclusion that the resistor is not needed for any application. The "needs a resistor" thing is probably just a modern day old wife's tale.

Yes, everything you read now says you need a resistor if the receiving vehicle has a gauge only. And everything will work fine with a resistor (or just a 194 bulb and socket. But why?

My '88 Burb has the newer style alternator with the newer connector, it also has the older gauge cluster with just a gauge... there is no warning light. It's a factory application and works fine without a bulb or resistor.

I upgraded to the newer alternator in my old '86 Camaro. I had ordered the adapter harness from Powermaster (I think) and they did not ask if I had an idiot light. The harness that was shipped had no resistor in it, and it worked fine. Then the cheap materials in the adapter harness started giving me connection issues, so I ended up splicing a new connector right into the original wiring. Everything is still working fine to this day.

I did the same thing to my other '86 Camaro. It also still works fine without a resistor.

I think the reason you need a resistor is the same as not setting a car battery on concrete.
 

85K10

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Alternator

Well I got my adapter from Rock Auto and its not the correct one. The photo shows it to have the resister. They sent the same part number but a connector without a resister.
 

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bucket

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Well I got my adapter from Rock Auto and its not the correct one. The photo shows it to have the resister. They sent the same part number but a connector without a resister.

I'd just try it and see if it works. Worst case, it just wouldn't charge... but I'm curious to see if it would work. I think it will.
 

85K10

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85K10

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Finally

Well I finally got the right plug in the mail today. It has the resister built in.
 

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usar17

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To bring this back up.

Whats the difference in the connections between these two styles. I'm going from an 1985 to a 1990 alternator with my serpentine swap. I know the brown wire can splice right into the newer connector, but what about the second wire that is present in the 80s style? The Alt plug to rear terminal- I'm assuming this is the sense wire...
 

myC-dime

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Whats the advantage of the different alt.?
 

8T6K5

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More amps....
 

usar17

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Do I need the sense wire? Or why don't the gmt400s have one
 

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