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keeping this old girl running is always fun. I got the red battery warning after my son left the right street parking light on a long time one night. Connected the charger and let it charge fo a few hours but to no avail, same warning.
replaced the voltage regulator and I’m getting 14.44v at the alternator post but only battery voltage at the main battery.
I presume this means the BCM? Very open to opinions. Thanks!
To further complicate issues, remembered I haven’t checked on the starter battery in a long while. It turned out to be bad, so I replaced it.
Now the alternator is not putting out any power.
Verified the connection at the BCM is not corroded. Verified continuity between supply and distribution at the trunk and passenger floorboard prefuse blocks.
Aux battery relay clicks when I test it.
here’s the read out from the BCM from my autel while the car was running. My xentry was at home. Consumer battery is pretty fresh and tested good for state of health and state of charge.
You can reset the BCM by disconnecting it for approx 10 minutes. A low voltage situation has been described in tech bulletins as putting the BCM in a safe mode. Remove power from the BCM to reset.
Go to charm.li and look at the WIS online or download the .zip file and install on your computer. There is an excellent section under the charging system that will walk you through an end-to-end troubleshooting of the entire charging system stem to stern. I have a few posts on it. Use "advanced search" upper right with my user name and you can find them. Only a few months since I posted them.
FWIW, Alexhemi just replaced a failed BCM. Available on eBay so I purchased a spare.
Last edited by bbirdwell; Nov 18, 2025 at 02:34 PM.
I guess progress? Disconnected the batteries for 10 minutes. Still getting the red battery signal and no voltage from the alternator, but the code is saying that there is no signal at terminal 61. Which is the signal wire from the ECU for charging voltage. I guess this explains why the alternator is not putting out power now.
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