I have an overcharging problem with my '06 Ram 3500 (5.9L). The ECM is putting out 14.6v and boiling (overcharging) my passenger side battery. How do I over-ride the ECM to get it down to 14.1v??

 

That voltage should be fine. How old is the battery?

 

batteries both replaced Sept 2019. The previous pair boiled before I knew what was going on.....

 

When I had my '02 it would run around 14.6 Volts (With a radar detector and charger for my phone), which I would assume is normal...

 

As already said, 14 is fine and where it should be. What type of batteries?

Have the batts replaced under warranty and see what happens. I know thats not good answer but unless you have a alt going out or the PCM is flaking out, its really all you have

 

batteries were warrantied when I first boiled them. The alternator and belt tensioner replaced with new batteries. Thanks for the reply. I will post if I am able to fix the issue......

 

Check the crossover cable and connections between the two batteries. Check for proper grounds on both batteries. Just an idea..for eg: if drivers battery is showing low on charge due to poor cable or connection , ecm may be demanding more current from alternator and overcharging passenger battery when drivers battery is the one needing the juice....

 

thanks for the crossover and terminal details. We have run through everything twice but will again.

 

I will have a look in see at mine tomorrow. I believe the main wire of the alternator is tied to the passenger battery. Not sure where the pcm picks up main 12v supply....but if it's on drivers battery...that could be a clue...???😕

 

Alt is definitely tied to passenger battery for 12v signal.