Check gages light came on yesterday. Codes P2609 No (yes, it says "no", I assume it means "low") voltage drop, & P2503 Charging system; DTCs read from my Smarty. Voltage is around 12.5. Got two new P2 batteries last month and I've got a long trip in 3 days.

 

I had the same issue a while back. Took off and cleaned all the cables and found one loose. I gooped the tops of the connectors with dielectric silicone grease and secured the connectors to the battery. I have not had an issue since. I hope it is this easy for you.

 

Thanks. But I found today to my surprise a smoked and burnt positive battery post on my new P2 battery (passenger side). Never would have guessed that could happen. Don't think I've seen one like it. Now, what caused it? Truck is down for now.

 

Completely disconnect the bad battery........you can run it on one battery temporarily.

 

I've had way more batteries fail in the first couple months than ones that fail near the end of their warranty.
Just because a battery is new don't assume it's good.
Luckily most batteries have a free replacement warranty for a few months to a year.

 

Took both batteries in to Sears today. Both dead'rn doornails. They are charging them to see if they hold. If they do, is it my alternator that fried em? I crawled all around looking for exposed wires; didn't see anything but did put some loom on the a/c compressor wire. Looked like it might of had a little rub.