Alternator conversion question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lile · 03-20-2006, 03:08 AM

Hi all,

I've got a question for the electrical gurus about a 10dn to 12si alternator swap. Everything I've read indicates on the regulator connector jumper F to 4 (16DBL to 16BRN) leave 2 and 3 (R and W) disconnected. On the alternator tie terminal 2 to BATT and terminal 1 to 16DBL from the 10dn harness, which is jumpered to the F (16BRN) at the regulator connector. Connect the charging wire 12R to BATT, discard the old relay wire (16W) and either discard the ground (12B) or ground it to the alternator case. Discard the old regulator.

A fairly big deal is made about not eliminating the 16BRN->16DBL->1 connection because it goes to the "generator idiot light" and therfore energizes the field so if it's disconnected the alternator will never start charging.

I can't find my "idiot light", maybe that's freudian. I've got a guage dash - speedo, ammeter, temp, oil pres, fuel. The indicator lights are high beam, brake, temp and L&R directionals. I don't think my ammeter is working, never moves, is that going to be a problem? The VIN is CE140Z14xxxx, if that helps.

Any clues? Is my new alt going to charge? Where should the "idiot light" be in the cluster?

Thanks!

--
Larry

KAILUAZ · 03-20-2006, 10:24 AM

Everything you need to know and great parts/customer service too.
http://www.madelectrical.com/index.shtml

farside847 · 03-20-2006, 12:07 PM

My bat guage was fixed by replacing my two little 4amp fuses under the hood.

67chevemall · 03-20-2006, 12:11 PM

gauge dashes don't have the idiot light, but they should....

lile · 03-20-2006, 12:21 PM

Both the 2a fuses for the ammeter were broken and the holders were in too far gone to be salvaged so I replaced the holders and fuses with mini-ato's. I was guessing it was the printed circuit in the dash. I just pulled the dash and sure enough the circuit was broken around the ammeter connection, so that's fixed.

I've replaced the printed circuit and all the bulbs and now know for sure that there is no idiot light for the generator.

Does anyone know if there are any dash harness mods that would need to be made or should it just work after the engine harness mods?

Longhorn Man · 03-20-2006, 03:46 PM

no under dash mods are needed. Just jump the wires and replace the plug, and all will be fine. There's quite a bit on this in the FAQ.

**truckdude239** · 03-20-2006, 04:45 PM

http://67-72chevytrucks.com/vboard/s...d.php?t=119379 here you go

lile · 03-20-2006, 05:01 PM

Okay, great. I had read through the faq and several others and everyone mentioned making sure not to miss the wire to the light and not having a light concerned me.

> The brown wire runs the the idiot light/gauge in the dash and is there for resistance
> to the internal voltage regulator. You can not skip this as it tells the regulator what it
> needs to be doing and when.

Thanks everyone!

**VetteVet** · 03-20-2006, 08:25 PM

Here is a thread in the FAQS that will help you with the conversion.

http://http://67-72chevytrucks.com/vboard/showthread.php?t=157126

03-20-2006, 03:08 AM	#1
lile Registered User Join Date: Aug 2005 Location: Simi Valley, CA Posts: 13	Alternator conversion question Hi all, I've got a question for the electrical gurus about a 10dn to 12si alternator swap. Everything I've read indicates on the regulator connector jumper F to 4 (16DBL to 16BRN) leave 2 and 3 (R and W) disconnected. On the alternator tie terminal 2 to BATT and terminal 1 to 16DBL from the 10dn harness, which is jumpered to the F (16BRN) at the regulator connector. Connect the charging wire 12R to BATT, discard the old relay wire (16W) and either discard the ground (12B) or ground it to the alternator case. Discard the old regulator. A fairly big deal is made about not eliminating the 16BRN->16DBL->1 connection because it goes to the "generator idiot light" and therfore energizes the field so if it's disconnected the alternator will never start charging. I can't find my "idiot light", maybe that's freudian. I've got a guage dash - speedo, ammeter, temp, oil pres, fuel. The indicator lights are high beam, brake, temp and L&R directionals. I don't think my ammeter is working, never moves, is that going to be a problem? The VIN is CE140Z14xxxx, if that helps. Any clues? Is my new alt going to charge? Where should the "idiot light" be in the cluster? Thanks! -- Larry

03-20-2006, 10:24 AM	#2
KAILUAZ King of Rust Join Date: Jul 2005 Location: St Petersburg, FL Posts: 359	Re: Alternator conversion question Everything you need to know and great parts/customer service too. http://www.madelectrical.com/index.shtml __________________ 1970 GMC 2500, 350, TH400, front disks, thats it! My Pics Last edited by KAILUAZ; 03-20-2006 at 10:25 AM.

03-20-2006, 12:07 PM	#3
farside847 Registered User Join Date: Feb 2005 Location: Bay Area, California Posts: 995	Re: Alternator conversion question My bat guage was fixed by replacing my two little 4amp fuses under the hood. __________________ 1971 Chevy C10 Shortbed Stepside, 307v8 3-on-the-tree

03-20-2006, 12:11 PM	#4
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Re: Alternator conversion question gauge dashes don't have the idiot light, but they should.... __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

03-20-2006, 12:21 PM	#5
lile Registered User Join Date: Aug 2005 Location: Simi Valley, CA Posts: 13	Re: Alternator conversion question Both the 2a fuses for the ammeter were broken and the holders were in too far gone to be salvaged so I replaced the holders and fuses with mini-ato's. I was guessing it was the printed circuit in the dash. I just pulled the dash and sure enough the circuit was broken around the ammeter connection, so that's fixed. I've replaced the printed circuit and all the bulbs and now know for sure that there is no idiot light for the generator. Does anyone know if there are any dash harness mods that would need to be made or should it just work after the engine harness mods?

03-20-2006, 03:46 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Alternator conversion question no under dash mods are needed. Just jump the wires and replace the plug, and all will be fine. There's quite a bit on this in the FAQ.

03-20-2006, 04:45 PM	#7
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,238	Re: Alternator conversion question http://67-72chevytrucks.com/vboard/s...d.php?t=119379 here you go __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

03-20-2006, 05:01 PM	#8
lile Registered User Join Date: Aug 2005 Location: Simi Valley, CA Posts: 13	Re: Alternator conversion question Okay, great. I had read through the faq and several others and everyone mentioned making sure not to miss the wire to the light and not having a light concerned me. > The brown wire runs the the idiot light/gauge in the dash and is there for resistance > to the internal voltage regulator. You can not skip this as it tells the regulator what it > needs to be doing and when. Thanks everyone!

03-20-2006, 08:25 PM	#9
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Alternator conversion question Here is a thread in the FAQS that will help you with the conversion. http://http://67-72chevytrucks.com/vboard/showthread.php?t=157126 __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. Last edited by VetteVet; 03-20-2006 at 08:27 PM.



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