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Sorry, forgot to add: According to "Fivetears" above, (Orange/Black) (Circuit 6752) is the Class 2 Serial Data wire. Connects to the main splice pack (SP205) for Pin 2 of the OBD2 Data Link Connector. Does this mean I can just go ahead and not worry that this wire is going to the instrument cluster, and I can just go ahead and connect it to the Pin 2 of the OBD2 connector??? If that is all, then my mystery is solved. Thanks!
Sorry, forgot to add: According to "Fivetears" above, (Orange/Black) (Circuit 6752) is the Class 2 Serial Data wire. Connects to the main splice pack (SP205) for Pin 2 of the OBD2 Data Link Connector. Does this mean I can just go ahead and not worry that this wire is going to the instrument cluster, and I can just go ahead and connect it to the Pin 2 of the OBD2 connector??? If that is all, then my mystery is solved. Thanks!
Have you tried this yet? I found this on another site:
Originally Posted by clinebarger
So is 100%
"When there is loss of class 2 communication with the powertrain control module (PCM), the module will send 100% duty cycle, 13.8 volts"
"Between 0-5 percent and 100 percent are for diagnostic purposes"
"the generator battery control module is limited between 36-90%"
This is excellent information. Confirmed a lot of things for me. Extremely helpful...below completely applies to my 06 charging system:
SARVC systems (found mostly on trucks) do not use the BCM for operation. They have a generator battery control module mounted to the negative battery cable, to interpret battery current and voltage and battery temperature inputs. The battery current sensor is internal to the module. This module also directly controls the generator L terminal duty cycle instead of the ECM/PCM.
Hey Guys, I hope it's ok to post here. I need some help with a project and It looks like there is a HUGE amount of knowledge here...
Here's my question/problem. I've got an GM LSA Engine and Trans with a stand alone ECM and TCM from GM going into an 07 chevy 1500. From what I can see is Both the ECM and the Vehicle have the high speed "LAN" Communication system, and i'm wanting to see if the stock gauges will work. I'm not sure if i can just tap the new ECM LAN connections into the original ECM LAN connection and everything will work or will there be a need for programming? I'm hoping the ABS, BCM, etc. will keep working and the ICP wont look like a Christmas tree.
Thank you in advance for any and all help, it's the first time i've done a project like this.
Just wanted to see if anyone else has had luck getting their alternator fully functioning. I'm wrapping up the wiring on my swap and the GBCM is my last stumbling block since there seems to be so much misconception out there. I'll be trying this in the next week or 2 but was hoping to verify that connecting the orange/black serial data wire to PCM serial data is the answer to getting a fully functioning alt with 14+ volts.
Sent you a PM Hart_Rod to get your feedback as well. Any feedback would be appreciated!
Of all the searching I've done this is the only thread I've found that even comes close to a solution rather than bypassing the module and deal with the 13ish volts or to swap regulators, etc...
Originally Posted by Hart_Rod
2 wires to the alternator, 2 wires to the battery, 2 wires to ground, 1 wire to serial data port - BOOM!!, it works!!!!
Just wanted to see if anyone else has had luck getting their alternator fully functioning. I'm wrapping up the wiring on my swap and the GBCM is my last stumbling block since there seems to be so much misconception out there. I'll be trying this in the next week or 2 but was hoping to verify that connecting the orange/black serial data wire to PCM serial data is the answer to getting a fully functioning alt with 14+ volts.
Sent you a PM Hart_Rod to get your feedback as well. Any feedback would be appreciated!
Of all the searching I've done this is the only thread I've found that even comes close to a solution rather than bypassing the module and deal with the 13ish volts or to swap regulators, etc...
After connecting mine as stated above, it worked as advertised.
Just a FYI for everybody if you are running an older pcm. The red/green pcms like the popular 411 do not have the programming to make the system work. The blue/green pcm's work if you tell them that they have the system that's why you need to have the data link connection. If you have a blue/green and it doesn't work you need to program it to turn on.
Hart Rod. What data wire did you run the orange/black wire to in the harness? Mine went through the instrument cluster on an 07 classic. I know this is an old post. Thanks ahead of time for any info!
Last edited by bustedknuckles67; 02-20-2020 at 04:45 PM.
Hart Rod. What data wire did you run the orange/black wire to in the harness? Mine went through the instrument cluster on an 07 classic. I know this is an old post. Thanks ahead of time for any info!
You can see what was written in the posts above...this mean I can just go ahead and not worry that this wire is going to the instrument cluster, and I can just go ahead and connect it to the Pin 2 of the OBD2 connector....
That will work.
Does the GBCM need to have the battery ground going through the plastic loop? I have relocated my battery and the negative wire is no longer next to the GBCM. Can i just use a engine to frame ground to run through the GBCM if that is needed for the GBCM.
I would think that this would not work. GBCM has to be close to the battery in order to work correctly.... at least from all the reading I have done. You would be better off to connect it in the factory fashion and just extend the battery negative cable if needed. I have never taken these apart so not sure what is involved but mine works perfectly after wrapping up my swap and I actually had to move my battery to the 06 Silverado location so that I can have the GBCM close to the battery like OEM . If it can be altered, someone else may have done it here and may chime in, but you may be better off then just removing the GBCM then playing around to see if it can be modified to work in your fashion. lt1swap has more info on this now. Just my 2c.
..and when you say does it have to go through the plastic, well, I think this is a unit you can not alter, this is why I stated I have never taken one apart so not sure how it measures current there but I would not try to take that apart unless someone else has. Hope this is what you were referring to.
Yes that is the unit i am talking about. I don't know how it actually works either. It kinda just sits on the Neg cable, but does not tap into the cable or anything. So i just don't know if i need to move it next to my frame mounted battery, or can i just sit it next to any Neg ground cable. I guess i can just set it up away from the battery and test the voltage. From what i am reading the voltage defaults to 13.8v if the GBCM is not working properly.
06-04-2018, 10:06 AM
