I also posted this in the conversion/hybrid forum but figured you drag race guys could help me out on this as I'm reworking the factory engine harness, deleting all the unnecessary stuff.

I'm working on the harness off my 06 silverado and I've hit a small road block. I'm trying to figure out what to do with the Generator Battery Control Module. Here are some options, but with questions:

1. Keep it.
If I do end up having to use it, do I have to put it back near the battery or can I put it on the ground cable that goes from the motor to the frame? If I have to put it back near the battery then I'll have to run some additional wires back up to the front to hook back into the harness. As far as I'm concerned this is the **** option.

2. Get rid of it. Ok, how? I did a ton of searching on the forums tonight and I can't seem to find any definate answers. If I can get rid of it, how hard would it be to convert to a one wire alternator, and how do I get the factory volt gauge to work?

I did a ton of searching on the forums tonight and I can't seem to find any definative answers on deleting it. I have seen where some people take the brown and grey wire from the alternator to a switched 12v source with a resistor on one of the wires. But I can't find an answer on what to do about the rest of the wires. If I remember right, there are 7 wires that connect to the GBCM. 2 appear to be grounds (black w/white stripe), 2 feed into the under hood fuse box (red w/black stripe), 1 wire that appears to go back into the cab, possibly for the instrument cluster (orange w/black stripe) and then the brown and grey to the alternator.

My truck appears to be different than any year model before it as the research I've done shows the 05 and earlier trucks with the alt. wires going to the pcm. Mine don't.

I would appreciate some help on this, I sure its been done, I just haven't found anyone that knows how to do it.

 

I've programmed an 05 with a GBCM to a 04 operating system to eliminate it, and it worked just fine. Gauge worked and everything. Don't know if that helps at all.

 

What is different in the 04? What do you mean by "programmed to eliminate it"? are you talking about disabling the associated DTC's?

 

04 year model didn't have GBCM's. I changed the 05 OS to an 04 to due away with it.

 

so did you get anywhere with this. i want to delete it as well for transplant in an aftermarket project.

 

I'd like to know as well

I have a 2006 5.3, if I change to an '04 OS, can I still use the alternator I have?

 

How many wires actually connect to the alternator? I haven't messed with one of these but it seems like you should just be able to excite the alternator with a fused switched ignition and delete the box.

 

my concern is; there is a "data" wire going from the ECM to the GCM. i'm afraid if i eliminate it the ECM will throw a code. this is for a customers turnkey harness. i'd like to eliminate it just for simplicity and to tidy up the engine bay. i haven't got confirmation from the tuning guy if there are parameters for the GCM in the tune via HP Tuners.

 

The voltmeter in the factory dash works without the this plugged in. As a matter of fact, it worked without the entire engine/trans harness plugged in.

I talked to some alternator shops and they can convert an ls style alternator to one-wire, so that would allow the alternator to work without being hooked to the pcm or gbcm.

I've since converted to a stand-alone harness for a 411 pcm so I can't say for sure that the remaining vehicle electronics would be happy without it using the factory 2006 wiring, but I can't help but think all would be fine by turning the related dtc's off.

I'm am going to be using a one-wire on my new setup so the alt. will not be controlled by the pcm.

 

I haven't tested this yet, put as posted on another similar thread:

i ended up eliminating the battery control module. the ECM has pinouts for both alternator connections and wire colors match. The wires originally went from the alternator to the Battery Control Module and the brown & grey wires went from the ECM to the Battery Control Module. I eliminated the BCM and simply connected the 2 wires together. after researching the function of the BCM, it appears that it only GETS info from the ECM via the data wire. The BCM uses info like, rpm, vss, tps, etc to maximize charging and fuel mileage and minimize emissions.

Blue ECM Connector
15 - Brown - Generator Turn on Signal
52 - Grey - Generator Field Duty Cycle

 

What's the part # on the 1 wire alt you'll be using?

 

I dont have the part number in front of me but I ended up just using a universal power master

 

Would that wiring solution work to control a gen 3 alternator with an E67 Gen IV ECM? I converted my engine to Gen IV and want to re-use my almost new alternator.