Alternator Dilemma

[nsb29]

I have a 2009 6.0 out of a Pontiac G8 my understanding is it is controlled by the ECM. My 65 C10 has gauges that I would like to continue to use, Has anyone else worked through this? My local shop doesn’t know for sure if it can be done but is willing to take a look, or possibly an earlier alternator that would be interchangeable

[kipps]

The gen 4 engines use a three wire "battery current sensor". This functions as an ammeter, and is clipped on the negative(sometimes the positive) battery cable. All three wires from this sensor go directly to the BCM. The BCM talks with the ECM through the GMLAN data lines, and tells the ECM how to adjust the alternator output.

You have several options. Listed below from best to worst.

1. Use the gen 4 alternator with the BCM and current sensor.

2. Swap the gen 4 alternator for a gen 3 alternator. This allows it to internally regulate the voltage.

3. Swap the voltage regulator within the alternator for the gen 3 version. This effectively converts your gen 4 alternator to a gen 3 style. However now, you no longer have an off-the-shelf alternator for easy replacement.

4. Use your gen 4 alternator with no BCM or current sensor attached. Leave it wired to the ECM as stock. It will enter a "fail-safe" mode, and will continuously charge at 13.8 volts. Many folks do this out of simplicity. This will theoretically compromise battery life, charging capacity, and fuel economy.

[nsb29]

Sounds like swapping out to a generation three would be the way to go, and it should still fit in the lower position where it’s at now you don’t have a model number by any chance

[nsb29]

Never mind I found it thanks for your help

[Daaaanz67]

I think member Hartrod made this work without a BCM. Check his post.

[kipps]

Originally Posted by Daaaanz67

I think member Hartrod made this work without a BCM. Check his post.

If you're referring to this thread, Hart_Rod used option #2 listed above.

[nsb29]

Thank you for the input I have already gone to option 2 with the help of the forum and my local generator shop, Who I found out is retiring after 40 something years don’t know what will do without him. I also am changing to a voltmeter so I can still have my gauges. I did run into one small problem as the earlier alternator case was slightly larger and head to you grind a little off the bracket to make it work but no big deal. Thanks again

[Daaaanz67]

Originally Posted by kipps

If you're referring to this thread, Hart_Rod used option #2 listed above.

Nope there is another one. I’ll try to find it nut don’t know how to link to this thread.