I got a buddy thats got a 06 cummins dually that if he parks it a while the batts go dead , he had it in the shop several times,they can't seem to fix it. If anyone has any ideas please let me know thanks.

 

a friend had the same problem with his '06. they replaced his alternator and that fixed it

 

just talked with my friend, he says dodge had a bunch of bad battery's in that year.. if you let the truck set for a few days the batteries will go dead, but drive every day and they will test good.... come to find out, changing the alternator didn't fix it, the dealer he bought it from in Las vegas NV said he had a lot of battery's in that year that he replaced

 

Just went through the same thing. Had to replace the batterys. They both tested OK, but if you left the truck sit overnight they would be dead in the morning.

 

that is really strange, i would think if a battery is bad it would test bad.... but then i used to test battery's with a hydrometer which they can't use with these new sealed battery's........ maybe the new test is better??? i don't think so

 

The batteries must have had internal low resistance paths between the terminals. Could happen.

 

Had the same problem in my 05 fine for about 2 day's and dead on the third. new batteries was the fix.

 

I have the same problem with my truck. I have isolated the issue to the gauge/dash cluster. If I leave it sit it will be dead in 24-48 hours.