LS Tech Headache Relief
Thread Starter
Teching In
Joined: Jun 2019
Posts: 3
Likes: 0
From: SLC Utah
LS Tech Headache Relief Project: 1978 Chevy C30 Repower W/ 2001 GMC LQ4 6.0
My experience! 40 years of grinding my teeth on GM's.
Today's headache. My aftermarket Gen 3 wire harness is configured for one lead from the ECM to the alternator. My 2001 GMC two wire alternator could be replaced however will my ECM still be configured correctly for the signal without a pin ground for that reference. I want the computer to control the alternator as designed. Looking for headache relief. Thanks From Rancho!
My experience! 40 years of grinding my teeth on GM's.
Today's headache. My aftermarket Gen 3 wire harness is configured for one lead from the ECM to the alternator. My 2001 GMC two wire alternator could be replaced however will my ECM still be configured correctly for the signal without a pin ground for that reference. I want the computer to control the alternator as designed. Looking for headache relief. Thanks From Rancho!
Last edited by rancho el rae 78; Jun 19, 2019 at 09:01 PM.
Yessir. I’ve been doing full builds since a teenager. I’ve got a couple magazine builds. Lots of builds no one here has ever seen, since they have sbc’s. My shop is my man cave. I go there to relax. I was in SLC two weeks ago. That’s the most beautiful place I’ve ever seen! Can’t wait to go back. Road trips rock!
Thread Starter
Teching In
Joined: Jun 2019
Posts: 3
Likes: 0
From: SLC Utah
Alternator Provisions / Aftermarket Harness Headaches
Early GM, AD series alternators and my particular "aftermarket harness" with one alternator wire required rework.
Those who wish to maintain proper ECM control over the charging system as designed can rest
assured I did not rest until this question was answered.
Parts Truck: 2001 GMC Sierra 2500 SL.
Specifics: Warren ECM For GMC Truck 2001 LQ4 6.0, Gen 3 80/80 red/blue straight pin connectors
Alternator - Delphi AD244 4 pin "two wire" connections.
Factory harness alternator pigtail "4 pin" two wire BROWN / GRAY
BROWN = L terminal on the alternator 4 pin recess.
GREY = I terminal on the alternator 4 pin recess.
(BROWN Corresponds to ECM Circuit 2128 and Pin #66 on the RED pin bar.)
Note: Your aftermarket harness may have Pin # 71 with continuity to BROWN. I removed this pin and wire from the clip for Pin 71.
GM Manual specifies circuit #71 is not used. I found the factory clip with Pin #71 had no continuity with my BROWN
lead from the alternator; verifying the factory claim.
GREY Corresponds to ECM Circuit 2124 and Pin #29. This will be your addition to make. You may utilize a pin with enough wire from an old pin bar or buy new terminal. Simple after completing. Took me all day. WTFa La La.
Quick Notes:
Red ECM Connector - Pin #66 and the L terminal on the alternator 4 pin receptacle; one wire section.
Pin # 29 and the "I" terminal on the alternator 4 pin receptacle; one wire section .
Hope this helps you spend more time with your wife and kids. Bless Gearheads Forever! From: Doug Burd
Early GM, AD series alternators and my particular "aftermarket harness" with one alternator wire required rework.
Those who wish to maintain proper ECM control over the charging system as designed can rest
assured I did not rest until this question was answered.
Parts Truck: 2001 GMC Sierra 2500 SL.
Specifics: Warren ECM For GMC Truck 2001 LQ4 6.0, Gen 3 80/80 red/blue straight pin connectors
Alternator - Delphi AD244 4 pin "two wire" connections.
Factory harness alternator pigtail "4 pin" two wire BROWN / GRAY
BROWN = L terminal on the alternator 4 pin recess.
GREY = I terminal on the alternator 4 pin recess.
(BROWN Corresponds to ECM Circuit 2128 and Pin #66 on the RED pin bar.)
Note: Your aftermarket harness may have Pin # 71 with continuity to BROWN. I removed this pin and wire from the clip for Pin 71.
GM Manual specifies circuit #71 is not used. I found the factory clip with Pin #71 had no continuity with my BROWN
lead from the alternator; verifying the factory claim.
GREY Corresponds to ECM Circuit 2124 and Pin #29. This will be your addition to make. You may utilize a pin with enough wire from an old pin bar or buy new terminal. Simple after completing. Took me all day. WTFa La La.
Quick Notes:
Red ECM Connector - Pin #66 and the L terminal on the alternator 4 pin receptacle; one wire section.
Pin # 29 and the "I" terminal on the alternator 4 pin receptacle; one wire section .
Hope this helps you spend more time with your wife and kids. Bless Gearheads Forever! From: Doug Burd
