GM alt wires - The 1947 - Present Chevrolet & GMC Truck Message Board Network

short step · 01-14-2009, 07:54 PM

What are the wires on a 89 alt for 2 red , brn & brn/w
bob

**VetteVet** · 01-14-2009, 09:28 PM

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This should be the alternator you are referring to called a CS style. The diagram is showing how to convert one to the older chevy trucks. When you ask what wires go where by color it can be deceiving because different models used different color wires. Below is the terminals and where the wires go from them.

"P" Terminal (Phase Connection) - This terminal sends a signal to a relay, frequency sensing tachometer, or computer indicating alternator speed. This terminal may not be used - this is normal.

"L" Terminal (Charge Light) - This terminal is fed from the ignition through the charge light on the dash. This connection turns the alternator "on". Without a signal to turn "on", the alternator will not charge. However the "I" terminal may be used to turn this alternator "on", as described, instead of the "L" terminal. Please note that if there is a connection on the "I" terminal there will be NO connection on the "L" terminal.

"I" Terminal (Ignition) - This terminal is fed directly from the ignition switch to turn the alternator "on". Without a signal to turn the alternator "on", the alternator will not charge. However the "L" terminal may be used to turn this alternator "on", as described, instead of the "I" terminal. Please note that if there is a connection on the "L" terminal there will be NO connection on the "I" terminal. If there is a connection on the "L" terminal AND the "I" Terminal THEN the "I" terminal is NOT an "I" terminal but an "F" terminal (confused yet??).

"F" Terminal (Field Monitor) - This terminal sends a signal to the computer telling it how much field current is flowing (therefore the computer knows how hard the alternator is working). This terminal is not always used AND can only be used if the alternator is turned on by the "L" terminal.

"S" Terminal (Battery Sense Connection) - This terminal is larger than the others and provides the alternator with a precise battery voltage reading however, this connection may not used. When not used, the alternator will automatically sense battery voltage at the battery post.

my67chevytruck · 01-14-2009, 10:41 PM

confused as heck. i will save this as i am not too far from having to do this.

texanidiot25 · 01-15-2009, 02:05 AM

There is another way to wire it with out using the stock GM wiring at all. I'll take pics of how mine is wired, but we didn't use the stork wiring harness and voltage regulator on mine. The cab get's it's power off a fuse block that's on my batt. and the alt is wired up differently..

I'll grab pics friday/saturday.

01-14-2009, 07:54 PM	#1
short step Registered User Join Date: Dec 2002 Location: Ludlow,MA Posts: 145	GM alt wires What are the wires on a 89 alt for 2 red , brn & brn/w bob Last edited by short step; 01-14-2009 at 07:54 PM.

01-14-2009, 09:28 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,717	Re: GM alt wires This should be the alternator you are referring to called a CS style. The diagram is showing how to convert one to the older chevy trucks. When you ask what wires go where by color it can be deceiving because different models used different color wires. Below is the terminals and where the wires go from them. "P" Terminal (Phase Connection) - This terminal sends a signal to a relay, frequency sensing tachometer, or computer indicating alternator speed. This terminal may not be used - this is normal. "L" Terminal (Charge Light) - This terminal is fed from the ignition through the charge light on the dash. This connection turns the alternator "on". Without a signal to turn "on", the alternator will not charge. However the "I" terminal may be used to turn this alternator "on", as described, instead of the "L" terminal. Please note that if there is a connection on the "I" terminal there will be NO connection on the "L" terminal. "I" Terminal (Ignition) - This terminal is fed directly from the ignition switch to turn the alternator "on". Without a signal to turn the alternator "on", the alternator will not charge. However the "L" terminal may be used to turn this alternator "on", as described, instead of the "I" terminal. Please note that if there is a connection on the "L" terminal there will be NO connection on the "I" terminal. If there is a connection on the "L" terminal AND the "I" Terminal THEN the "I" terminal is NOT an "I" terminal but an "F" terminal (confused yet??). "F" Terminal (Field Monitor) - This terminal sends a signal to the computer telling it how much field current is flowing (therefore the computer knows how hard the alternator is working). This terminal is not always used AND can only be used if the alternator is turned on by the "L" terminal. "S" Terminal (Battery Sense Connection) - This terminal is larger than the others and provides the alternator with a precise battery voltage reading however, this connection may not used. When not used, the alternator will automatically sense battery voltage at the battery post. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

01-14-2009, 10:41 PM	#3
my67chevytruck Under Construction Join Date: Oct 2007 Location: Midlothian,TX (DFW) Posts: 4,555	Re: GM alt wires confused as heck. i will save this as i am not too far from having to do this. __________________ Heath subscribe to the board here: http://67-72chevytrucks.com/vboard/payments.php http://67-72chevytrucks.com/vboard/s...d.php?t=157669 FAQ how to's 1956 Chevy Apache 1967 C10 SWB FleetSide (under construction) 1969 K10 SWB FleetSide (Future Build) 1972 C10 SWB Stepside (Future Build) 56 chevy truck : http://www.cardomain.com/ride/2955823/1 67 truck build: http://www.67-72chevytrucks.com/vboard/showthread.php?t=281357/1 69 k10: http://67-72chevytrucks.com/vboard/s...d.php?t=389470

01-15-2009, 02:05 AM	#4
texanidiot25 Eat My Rust Join Date: Jan 2007 Location: Cypress, Texas Posts: 3,362	Re: GM alt wires There is another way to wire it with out using the stock GM wiring at all. I'll take pics of how mine is wired, but we didn't use the stork wiring harness and voltage regulator on mine. The cab get's it's power off a fuse block that's on my batt. and the alt is wired up differently.. I'll grab pics friday/saturday.



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