I suspect BCM... thoughts?

[TrybalRage]

Have you tested the alternator beside just checking the voltage output with a multimeter? If it's not properly charging the battery, that would explain just about everything.

I have not. To be honest I've never tested an alternator any other way. I know autozone and such offer an alternator test, what's different about it?

When running, it's over 14v, on multimeter and on gauge. If I go for a drive, come home, shut off vehicle, pop hood, battery tests at 12.7-12.8.

 

[intheburbs]

I have not. To be honest I've never tested an alternator any other way. I know autozone and such offer an alternator test, what's different about it?

When running, it's over 14v, on multimeter and on gauge. If I go for a drive, come home, shut off vehicle, pop hood, battery tests at 12.7-12.8.

I believe it's a load test. Volts don't matter if the amps aren't there. Again, if for whatever reason the alternator is bad, that explains just about everything. Simplest explanation is usually the correct explanation.

 

[Doubeleive]

I believe it's a load test. Volts don't matter if the amps aren't there. Again, if for whatever reason the alternator is bad, that explains just about everything. Simplest explanation is usually the correct explanation.

easy to find out just turn everything on headlights, wipers, defroster, heater blower, seat heater, radio, windows up/down, adjust seat back n forth and turn the key to run only to test battery

 

[TrybalRage]

easy to find out just turn everything on headlights, wipers, defroster, heater blower, seat heater, radio, windows up/down, adjust seat back n forth and turn the key to run only to test battery

But how would that load test the alternator? If the battery is fully charged (like I have it on a charger right now) it would be fine, and if it were already low it would just test lower?

 

[Fless]

Have you tested the alternator beside just checking the voltage output with a multimeter? If it's not properly charging the battery, that would explain just about everything.

^^ This. In addition to the voltage test it should be checked for how much current it's generating. Wonder if the RVC is working correctly?

Also a thorough check and cleaning of the battery cables and main grounds should be done, if it hasn't yet.

 

[TrybalRage]

^^ This. In addition to the voltage test it should be checked for how much current it's generating. Wonder if the RVC is working correctly?

Also a thorough check and cleaning of the battery cables and main grounds should be done, if it hasn't yet.

Yes, cables are clean, new main ground wire and an additional 4ga wire from the block to the firewall was added.

Guess I'll run it up to autozone tomorrow.

But I gotta be honest, a battery above 12v and causing the whole system to bug out seems... like more than just a low battery.

 

[Doubeleive]

But how would that load test the alternator? If the battery is fully charged (like I have it on a charger right now) it would be fine, and if it were already low it would just test lower?

you would see a heavy drop in voltage

 

[gpracer1]

There is more to testing an alternator than just volts and amps. They test to make sure the rectifiers are not bad, or you will have AC ripple which can cause havoc with data transferred between canbus modules.

 

[Geotrash]

There is more to testing an alternator than just volts and amps. They test to make sure the rectifiers are not bad, or you will have AC ripple which can cause havoc with data transferred between canbus modules.

^^^This.

I'm with the others here that the alternator is suspect at this point. And Autozone doesn't have any credibility with me when it comes to testing them in the car. The only way to do it right is with a bench test. At that point, you might as well just replace the thing. I've been running one of these in both of my trucks for a few years now, and no problems at all:

https://www.amazon.com/gp/product/B00SL6T29K/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

 

[donjetman]

^^^This.

I'm with the others here that the alternator is suspect at this point. And Autozone doesn't have any credibility with me when it comes to testing them in the car. The only way to do it right is with a bench test. At that point, you might as well just replace the thing. I've been running one of these in both of my trucks for a few years now, and no problems at all:

https://www.amazon.com/gp/product/B00SL6T29K/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

Me too, almost 4 yrs and 40k miles ago. No problem. $101 back then.