SI to CS Alternator Conversion
Thread Starter
Instructor
Joined: Mar 2009
Posts: 187
Likes: 1
From: WA
SI to CS Alternator Conversion
I have searched long and hard and can't quite find the correct wiring info, so I apologize in advance for asking redundant questions.
1971 vette with Ammeter, but will be switching to Voltmeter.
1) I have a brown 12v switched wire and a black/white constant 12v wire that went into the side of the alternator. Is it the switched 12v wire that connects to the "L" wire on the CS plug?
2) As far as I know, I don't have a generator/alternator light because I have an Ammeter. Is this a correct assumption and therefore, I will need to add a resistor?
That should be it. Thanks as always.
1971 vette with Ammeter, but will be switching to Voltmeter.
1) I have a brown 12v switched wire and a black/white constant 12v wire that went into the side of the alternator. Is it the switched 12v wire that connects to the "L" wire on the CS plug?
2) As far as I know, I don't have a generator/alternator light because I have an Ammeter. Is this a correct assumption and therefore, I will need to add a resistor?
That should be it. Thanks as always.
Thread Starter
Instructor
Joined: Mar 2009
Posts: 187
Likes: 1
From: WA
Well heck, while searching something else, I believe I stumbled across the answer to #1 which is yes, I use the brown switched wire to the "L" connection.
Still not 100% sure on resistor, but thinking I should just do it to be safe.
Still not 100% sure on resistor, but thinking I should just do it to be safe.
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
I looked up Durango_Boy and found this thread.
http://forums.corvetteforum.com/c3-t...-question.html
http://forums.corvetteforum.com/c3-t...-question.html
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
Here: Do this to find you pigtail....
Try using this to figure out your adapter. Follow the guidance as written. Worked the first time for me. Go to your local parts store and get the equivalent pigtail part number:
The site below tells you how to figure out which adapter to buy for your CS-144 tie in to your 12SI: I also added the key paragraph below in case you cannot open it.
http://72.14.253.104/search?q=cache:...lnk&cd=2&gl=us
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
The site below tells you how to figure out which adapter to buy for your CS-144 tie in to your 12SI: I also added the key paragraph below in case you cannot open it.
http://72.14.253.104/search?q=cache:...lnk&cd=2&gl=us
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
Thread Starter
Instructor
Joined: Mar 2009
Posts: 187
Likes: 1
From: WA
Checked the resistance as described and I currently have 41 ohms. The instructions state that a 50 ohm resistor should be used. Gonna give this a shot. Let's hope I don't blow this baby in 6 months... 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
Oh well...that makes sense....
I first converted my 10Si to a 94 Amp 12 Si....when I went to the CS-144 I just got the adapter. Being paranoid I figured that if I ever needed an alternator I could then get a 12Si or CS-144 and either would plug right in if I had the adapter.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
[QUOTE=71_S-Ray;1578214047]I have searched long and hard and can't quite find the correct wiring info, so I apologize in advance for asking redundant questions.
1971 vette with Ammeter, but will be switching to Voltmeter.
1) I have a brown 12v switched wire and a black/white constant 12v wire that went into the side of the alternator. Is it the switched 12v wire that connects to the "L" wire on the CS plug?
YES The constant wire maybe able to leave disconnected as many CS144 alts have a internal reg sense jumper, making it redundant....
2) As far as I know, I don't have a generator/alternator light because I have an Ammeter. Is this a correct assumption and therefore, I will need to add a resistor?
that black white wire goes to a piece of resistance wire, going to the switched say ignition circuit .....now to replace with a red 'idiot light'.....you just add a 159 bulb...or like I did a lo current bulb from Radio shack, and jumper a 220 ohm resistor across that bulb....gives the alt a bit more kick, stays charging at idle....
That should be it. Thanks as always.
1971 vette with Ammeter, but will be switching to Voltmeter.
1) I have a brown 12v switched wire and a black/white constant 12v wire that went into the side of the alternator. Is it the switched 12v wire that connects to the "L" wire on the CS plug?
YES The constant wire maybe able to leave disconnected as many CS144 alts have a internal reg sense jumper, making it redundant....
2) As far as I know, I don't have a generator/alternator light because I have an Ammeter. Is this a correct assumption and therefore, I will need to add a resistor?
that black white wire goes to a piece of resistance wire, going to the switched say ignition circuit .....now to replace with a red 'idiot light'.....you just add a 159 bulb...or like I did a lo current bulb from Radio shack, and jumper a 220 ohm resistor across that bulb....gives the alt a bit more kick, stays charging at idle....
That should be it. Thanks as always.
