I have an 07 Dodge 5.9 cummins In January, the passenger side battery blew the cap off of the battery, and acid when all over the fender well. I replaced both batteries, with new ones, cleaned the battery terminals, posts, and tightened the terminals. Two days later, driving home from work, I started smelling the odor from the batteries, and noticed that the amp gauge was reading low. I stopped and opened the hood, and felt both batteries, driver side was cool, passenger side was hotter than he$$. I took the terminals off the posts, and cleaned them, then replaced the terminals back on the post. I bought a relay for the air intake heater grid, since the relay sits underneath the passenger side battery, and replaced the relay.

Never had any problems until yesterday. Again I checked the passenger side battery, and it was hotter than he$$, and it was leaking acid out the side of the battery, which are sealed, except for the small vent on the side of the battery. Again I cleaned the terminals and post on both batteries, and the amp gauge is running around 15. I can't afford to buy batteries every 8 months or so. Has anyone else experienced this? I am thinking about replacing the neg/pos battery terminals on the passenger side of the truck. Any suggestions would be appreciated.


Thanks in advance

 

Been a long time since I read anything like this, but at that point, the problem was determined to be a faulty ground between the crossover cable and the other battery.

15V isn't out of line going down the road, mine usually runs just a tick under 15, but I wouldn't want to go much higher unless temps were really cold.

You say whenever you clean the grounds things settle down for a while, is there any chance you battery cable is corroded under the sheath at one of the terminals?

 

I found some corrosion on the positive cable. Going to cut it off and replace the end. In the near future, I am going to replace all the cables on the passenger side battery.

 

Over charging the passenger side battery is common for these trucks. There are tons of threads already on this issue.

On the 3rd gen trucks, the ECM is controlling the alternator output.
The ECM is monitoring the drivers side battery and the alternator output is connected to the passenger side.

If there is any voltage difference or resistance between the 2 batteries, the ECM will continue to increase the cranking voltage causing the alternator to over-charge the passenger side battery while the drivers side battery is barely getting charged.

The most common cause is resistance in the cross-over cable between the 2 batteries. Corrosion near the connectors.

In a recent discussion, it was suggested to double up the crossover cable with a 2nd cable to prevent this issue in the 1st place.

 

I clean the connection really well and use battery terminal protector spray. Then there are some people that never open the hood, I can tell this by the corrosion I find on the terminals every time they come in for service.

 

Thank you all for the information. I may try the crossover cable as well.


I seem to be under the hood or under my truck all the time. I do all of the maintenance on my truck, so I try to look at everything and see if I notice anything out of the ordinary.