removal of generator battery control module

[rustycars63]

2005 5.3 harness trying to remove the Generator battery control module as I do not think it is needed in my 1949 Chevy truck . Any help will be appreciated .

[BR3W CITY]

Bypass the wiring, have your tuner flash the ECM with a 2004 O/S. You won't lose anything you'd need in your swap, and it deletes all the GBCM functions.

[rustycars63]

Thanks very much for your input will give this a try .

[ls1nova71]

You will have to wire it like an '04 also. There aretwo wires that go to the PCM. You may also need an older alternator, the one with the flat plug. When I did my '06 with the round plug, even with it wired and tuned for an '04 it still defaulted to 13.8v.

[rustycars63]

Thanks , i am side tracked on truck for the moment but will follow your advice , thanks again.

[Hart_Rod]

Originally Posted by ls1nova71

You will have to wire it like an '04 also. There aretwo wires that go to the PCM. You may also need an older alternator, the one with the flat plug. When I did my '06 with the round plug, even with it wired and tuned for an '04 it still defaulted to 13.8v.

Mine defaulted to 13.3V (13.8V at the generator output), at least that's what my gauges are showing. I'm thinking about wiring the GBCM back in, as I see a pretty substantial (2V) when data-logging and going WOT and would like for the alternator to put out more voltage when the situation arises.

[ls1nova71]

I probably would if you have it. Seems to me it's a better way of controlling the alternator, and isn't really that much more wiring. It's a couple of power wires and some grounds, then the rest just go between the GBCM and the PCM so there's nothing really to be done. You will have to splice the serial data wire, but that's about it. Here's a schematic in case you need it. The schematic is two pages, even though it looks like one, so that's why it looks funny. I cant put them all on one page and still be able to read them.

[71cadc10]

that string you listed on the connector, is not the part no. It is the recycling code for the plastic...FYI.

The Delphi p/n would be something like 6-8 digits just numbers.
do you have a pic of the connector maybe I could help ?

[rustycars63]

Thanks , for all the help looks like help desk is giving me 13545282 or new number 13545282 as plug number after sent photos to them. Customer service at Mouser .

[dayj1]

Originally Posted by rustycars63

Thanks , for all the help looks like help desk is giving me 13545282 or new number 13545282 as plug number after sent photos to them. Customer service at Mouser .

You probably already know this, but, just in case, the part number you have is for just the plastic housing. You still need the terminals for the appropriate wire size that you're using, the seals, and, possibly, crimpers to attach the terminals to your wires if you don't already have them.

[Wildkarde]

Eficonnection.com is a great source of LS connectors and they offer most of them as pigtails.

[Hart_Rod]

I hooked my GBCM up per the instructions/wiring diagrams. Nothing changed, still defaulting to 13.8 V. Does something have to be updated in the tune? Is there a way to troubleshoot the GBCM? TIA

[rustycars63]

Did you hook up the Blue wire , engine on signal , some say to store it as its not needed , but, does this control gbcm. The link to the acdelco information is no longer available that i can find. Just thinking out loud.

[Hart_Rod]

Originally Posted by rustycars63

Did you hook up the Blue wire , engine on signal , some say to store it as its not needed , but, does this control gbcm. The link to the acdelco information is no longer available that i can find. Just thinking out loud.

No blue wire in the harness that came with my GBCM. I wonder if I have to turn on the "L" terminal in the tune system options?

[rustycars63]

Not sure about tuning what year is your engine and harness ?

[Hart_Rod]

Originally Posted by rustycars63

Not sure about tuning what year is your engine and harness ?

Both 2006

[ls1nova71]

Originally Posted by ls1nova71

I probably would if you have it. Seems to me it's a better way of controlling the alternator, and isn't really that much more wiring. It's a couple of power wires and some grounds, then the rest just go between the GBCM and the PCM so there's nothing really to be done. You will have to splice the serial data wire, but that's about it. Here's a schematic in case you need it. The schematic is two pages, even though it looks like one, so that's why it looks funny. I cant put them all on one page and still be able to read them.

Originally Posted by Hart_Rod

I hooked my GBCM up per the instructions/wiring diagrams. Nothing changed, still defaulting to 13.8 V. Does something have to be updated in the tune? Is there a way to troubleshoot the GBCM? TIA

Rob, you're killing me, man!! I assumed you had that hooked up all along..... Well, we all know what they say when you assume something.....

[Hart_Rod]

Originally Posted by ls1nova71

Rob, you're killing me, man!! I assumed you had that hooked up all along..... Well, we all know what they say when you assume something.....

, long story short Eric, my GBCM harness didn't have the serial data wire in it, so I assumed it wasn't needed..... my bad..... It's all good now, .

And just to close the loop, my computer is a 2006 (nothing has to be changed in the tune to make the GBCM work).
The grey and brown wire from the 2006 GBCM harness goes straight to the alternator (nothing goes to pin C 15 or C 75).
Two reds/wht to 10 amp fused source.
Two black/wht to ground.
Orange/black to class 2 serial data line.
Blue wire was deleted.

For a 2005, I believe you may have to connect some wires to the computer (C15 & C75), but I'm not certain.

Eric - where would you recommend connecting into the Class 2 serial data line? Is there possibly an open pin in the PCM blue or green connectors that I could use? Thanks again for all of the help!

[Hart_Rod]

I checked the continuity of all my wiring and everything checks good. I also reflashed the tune with the "Alt L" turned on (1). I didn't get a chance to check it yet, but will this evening. I also found a pretty good article that goes more indepth of the GBCM system: http://www.flatrater.com/samples/Battery/rvc.html

[Hart_Rod]

Changed the tune, and still no difference in output and nothing on the scanner. The only other possibilities are, bad voltage regulator or bad GBCM?

[rustycars63]

Are you getting any codes ?

[Hart_Rod]

Originally Posted by rustycars63

Are you getting any codes ?

No, but I wasn't getting any codes before I wired the GBCM up

[Hart_Rod]

Found a slightly different wiring diagram for the GBCM in this thread:

https://ls1tech.com/forums/conversio...de-anyone.html

[Hart_Rod]

Played with a couple things last night, but nothing worked. Seems like there are 3 options left:

1. Get a new GBCM ($80)
https://www.gmpartsgiant.com/parts/g...-15263889.html

2. Replaced the voltage regulator.....
https://store.alternatorparts.com/d3...ternators.aspx

or

3. Convert to a 4 pin voltage regulator and say goodbye to the GBCM:
https://alternatorstarterrebuildkits.com/product/dr44/

[Hart_Rod]

Found another good article describing the RVC systems:

https://www.motor.com/magazine-summa...september2015/

"There are two types of RVC systems in use—integrated RVC and stand-alone RVC (SARVC). Integrated systems use a battery current sensor to inform a body control module (BCM) how much the battery is being charged or discharged"