Dead Batteries

[Bob Fennema]

I have been having problem with my 2004 SO 2500 since it was new. The batteries frequently are dead when I go to start the truck. It can happen while I am at work after being parked 6 hours, over night and aways after two or three days of being parked. Nothing works, no lights, door locks etc. I replaced the batteries and that made no difference.



I have a small battery charger that says 10 amperes but the ammeter never goes about 5 amps. I hook up and after only 10-15 minutes of charging, the truck will start. That doesn't seem like enough charging time.



Could I have a relay problem or something else? How do I troubleshoot this problem? The Dodge dealers near my home are both brain dead which I think is a qualifying trait to be a Dodge dealer. One told me it was my trailer brake controller. I remove it and the next morning, dead batteries. The other dealer - "nothing wrong" just the computers draining the batteries. Duh!



Help.



Bob Fennema ( the h\guy with the jumper cables on the front seat)

La Mesa CA

 

[JFaughn]

If you can get an amp meter hooked up to the battery then pull the fuse's one at a time untill the load goes away thats the system that is pulling it down .
The glove box lite is one that is tricky , like not knowing if the frig lite goes out when you close the door.

 

[Alan Reagan]

The easiest way to troubleshoot this is with an ammeter but it may take some time.



Disconnect both batteries. Connect the ammeter in series with one battery and cable. Make sure the ammeter is on the highest amp setting.



Check the current draw.



Then pull the fuses one at a time until you see a significant drop in current. You may start with the relays under the hood. You may have a relay stuck closed causing a constant current draw.



That should tell you what circuit is giving you the problem.



I had a similar problem on a car a few years ago. It was the glove box light staying on all the time. It would take it about two days to pull the battery down. That's how I found it.



If you don't have an ammeter and aren't comfortable, take it to a truck/auto electrical shop. They can troubleshoot it pretty quickly for you.

 

[jelag]

I'm going to disagree with most of the other posts... if like you say, you can have this happen after the truck has sets for 5 hours or so..... the draw to drain both batteries in this time would in fact melt the insulation on most wiring..... so you need to be looking for a loose connection..... The other key to what I suggest is that 20 min on a 10 amp charger is not enough time to take 2 batteries from dead to a point that the truck will start... .



When the truck doesn't start..... try the horn or turn on the lights... . if the horn or lights function correctly (they are high users of energy) than you batteries are up and there is another problem... . I'm guessing that you have a bad connection where one or more of the batteries connect to the ground circuit... . or the ground circuit from the engine to the body is bad...



How you find this is take one cable from a battery jumper set... . and jump from the ground on one battery to either the frame or engine when your problem occurs. . when the truck starts... . with the jumper cable in place you've found the circuit the problem is in..... all you need to do is find the problem...



I've personally spent 3 to 4 hours hunting for this kind of problem, the last time was my son's Pontiac Van..... 3 1/2 hours into it we found the bad connection that was causing the problem, cleaned it... . and its been trouble free for 6 months now... but we were forced to open all the ground connections and inspect the cable connection and clean it after it was unbolted..... His problem was dash gauges that went crazy and engine controls that would shut down the engine..... It was nothing more than a ground connection... .



Again from looking at the connection it was fine... when we unbolted the connection the dirt on the back side said it all..... Hope this helps...

 

[Alan Reagan]

Jelag,

I don't disagree with your assessment. What is strange is the fact that charging seems to fix the start problem.



I had a Pontiac that had the same problem and we never found it. But, as you said, the batteries weren't dead. I could turn the engine off and when I went to restart, there was nothing. Not even a click. Cleaned all the cables/ground connections and never found it. I figured it must have been the starter itself.



If he is jumping the truck off, then he is getting a good ground from the supplying vehicle.



I made my suggestion based on the fact the he said the batteries were dead. That must not be the case.



Good suggestion, on cleaning the contact points for the cables.