I have a 2001 Dodge Ram 1500 with the small V8. My truck started off with overcharging my battery so I thought it was the alternator and put a new one in it. That didn’t fix the problem it would do fine as long as I stayed under 30mph so the next step was put a new PCM in it. Did that and it worked fine for a day or two and went right back to overcharging the battery, but as long as my a/c was on full blast and my lights where on bright it did fine. Well today I killed the truck for about 2 minutes and went to crank it battery was dead (battery is only a month old) jumped it off drove about a hour or so and killed it again went to crank it and the battery is super dead. I’m not sure what the issue could be but I know myself and the local mechanic have no clue what is going on. Any help or advice would be greatly appreciated.

 

How do we know it's overcharging?

Consider the dash gauge useless, what other data can you provide us?

Either way it's possible to convert to an external regulator. I've not done it but the tech is out there with a search.

 

I’ve never collected anymore data then just going off the dash gauge. I’m not a mechanic by any means but I know if I drive it too long with the battery overcharged it’ll do some damage. If I stop and let the truck idle for a minute or so the gauge goes back to normal. I had someone suggest a external regulator, but after spending the money on a new alternator,pcm, and battery I wanted more than just one opinion before I spend money on it too.

 

You can use a tool like this to connect it to the battery's positive and negative terminals to determine how much voltage the battery is seeing when the truck is running - https://www.harborfreight.com/100a-6...ter-61747.html

 

I think it would be smart to do some testing first before throwing parts at it. You need to see what voltage is at the battery. If it's not charging it may have blown the fuse in the engine compartment distribution box.

 

Yeah, two PCM's doing the exact same thing, is well beyond 'unusual'.

 

okay so today I Jumped it off and took it to O’Rylies battery tested normal and alternator tested a little low but nothing that should be causing problems. I’m at a stand still I don’t understand what could be causing my truck to act like the battery is dead and I have to jump start it every time. However, since this problem started my issue with my battery over charging has seem to gone away my gauge is staying normal now. I’m not sure what it could be other than my truck is just dumb.

 

Poor cables/connections are the #1 overlooked problem, especially when the parts cannon is ready for firing.

I know you just replaced the battery but good practice to "cut" the posts and the cable ends with a terminal cleaner tool, helps make sure the post tapers match and your getting full surface contact, that also helps reduce corrosion points in the future, also make sure your cables are good condition, next check all your chassis ground points primarily the engine and pcm/body gorund cables, poor voltage or back feeding due to corrosion can both cause a lot of damage and create alot of headache symptoms, next I'd check the cable ends at the alternator and the cable running from the alternator to the battery

As far as acting like a dead battery, poor battery connections do it probably 85% of the time

Could also have a loose starter, loose starter cables, weak solenoid/contacts in the starter

Even if your not mechanical, if you plan to work on your own vehicles, good idea to have the basic tools and knowledge at the ready

A voltage drop test on the starter cable might be a great place to start

 

Yep, battery cables and grounds are ALWAYS a good thing to inspect.

Beyond that, if you're having to jump your truck, first check voltage at the battery. If it's over, say, 12V* then have someone try to start it while you watch for voltage drop at the battery. If voltage pulls way down the batt is weak (we can probably rule this out if you just had the battery load tested) or your starter may be unhappy and drawing excessive current.

*some will argue 12.8 but I've had old batteries at 11V start a Ford EFI 351 for months

If beginning voltage is too low you may have a parasitic draw somewhere. One dead simple way to verify this could be to remove your negative cable at night. If the truck happily fires up the next morning when the cable is replaced, then a parasitic draw looks more likely and you can verify with a DMM (there are tons of vids on YT)

If NO voltage drop occurs with key in START, it's likely the starter is not being TOLD to engage, and I would then check for voltage at the trigger wire down at the starter itself. The little trigger wire should only be hot with key in START position. I just recently learned if you're unfortunate enough to have the '99-03 starter BE CAREFUL with the stupid plastic connector for the trigger wire. If '98 and earlier it's just a ring terminal (soooo much better-er and smarter-er!!!!)

There is also a starter relay in fuse box and you could swap it with another relay (there's really only 2 styles under there) if voltage is good but starter is not engaging.

Anyway, those are places to start. We can guide you from there. DO NOT buy any parts yet, further diagnosis is required before spending $$

 

My dad thought it might have been the ground cable so he took it off and cleaned it put it back the truck still didn’t fire. He checked the wire that goes from the battery to the starter and all of that seemed to be tight and everything looked good. Knock on wood since jumping it off this last time I’ve killed it twice and restarted it 30 mins later and it worked fine. My luck though it’s probably still not fixed. I’m going to let him know what y’all have told me and try and go from there. I will keep y’all updated. I really appreciate all the help!