Gm 2 Or 4 Pin Alternator?

Jon Owner/Technician California Posted   Latest   Edited  
Resolved
Programming
2 Or 4 Pin Alternator??

I am setting up a 2010 Chevy Express 3500 6.0L to update the ECM/TCM and Techline Connect is asking for the alternator configuration, specifically if it has a 2 terminal or 4 terminal alternator installed. This van has a 4 terminal connector alternator however, there are only 2 terminals used. Is this a 2 or 4 terminal alternator for programming purposes? 

I figured this out by running the VIN through TIS and comparing the listed calibrations to the ones currently installed in the ECM. This is considered 4 terminals even with only 2 being used.

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Jon Owner/Technician
California
Jon Resolution
 

Solved-

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Thanks
Robert Mobile Technician
Delaware
Robert
 

The first time I had this I did it wrong. It only had two wires going into the connector so I assumed it was a two pin. Fortunately I was able to reprogram it to the correct one once I found out that I made the mistake. GM should have done a better job of clarifying what exactly they mean. Glad you got it resolved.

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Agree
Jon Owner/Technician
California
Jon
 

I originally thought the same thing - 2 wires coming out - must be a 2 terminal alternator… Thanks for the response-

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Dan Owner/Technician
Texas
Dan
 

Clarified… Dan H.

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Marlin Technician
Oregon
Marlin
 

GM is notorious for stuff like this, which can add a lot of time to reprogramming.

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Dan Owner/Technician
Texas
Dan
 

… If you UNPLUG the (two WIRE)connector … I take it that there are 4 PINS under it … right? … Dan H.

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Jon Owner/Technician
California
Jon
 

I don't know Dan - I didn't unplug it - I was able to deduce that it had 4 pins by looking at the back connector… because I'm smart like that…

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Funny
Mohammad Owner/Technician
Illinois
Mohammad
 

Here are the pictures of 2-Pin and 4-Pin Delco CS alternator/regulator pins. The 2-Pin is RVC (Regulated Voltage Control). The “L” is not light but a PCM 5V signal of 128 Hz which its pulse-width percentage set the charging voltage setting. F is the feedback. The 4-Pin is rather standard but only uses the 2 wires most of the time, PCM activates the alternator via a 10V signal (on that vintage…

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Craig Owner/Technician
Michigan
Craig
 

GM asked you if it was a 2-pin or 4-pin. Not what the wiring harness was. Problem solved. Sometime we over thing the question.

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