My bother has an 07 Dakota 4.7 and he recently had the battery replaced. After that there was a drain on the battery and it would go dead if he let it sit for a couple of days. He took it to a mechanic who told him that if you ever unhook the battery you have to reset the computer or there is some module that will stay on and drain the battery, is this true? I have heard of reprogramming the computer on some newer BMW and Mercedes cars after a battery change but not on a Dodge.

 

I've never heard of it. I've replace my battery a few times in my truck and never had an issue. Even the many times I've disconnected the battery, never an issue.

 

Disconnecting the battery resets the PCM. Not to sure about this "mechanic". Problem is most likely unrelated to the battery replacement.

 

That's what I figured, every vehicle I have worked on unhooking the battery resets the pcm, I haven't worked on many newer vehicles though. He also said something about Dodge used to ship vehicles with a 9 volt battery that you had to plug in somewhere under the dash while you changed the battery. I have never in my life seen or heard about anything like that.

 

There is an adapter, not specific to Dodge, that you can use as a backup when changing a battery to keep all your preset radio stations in tact.
I think I would find another mechanic, there is nothing to reset after changing a battery, I am on my third battery on my 05 and have never ran into any battery drain issues after changing one.

 

I was just checking I have changed many batteries and never heard of this. Before he took it to the mechanic I pulled the alternator off and got it tested and it was fine. I tested the amp draw with a meter and there was a .6-.7 amp draw with it turned off and it would go down to .2 amps when I pulled the radio fuse. However when I was doing my testing something would keep coming on shortly and going off my meter would jump to .5 then back down to .2. I didn't have time to mess with it so he took it to the mechanic, he just got it back today so we'll see if it is fixed.

 

Antoniocool had the same issue. That thread is about halfway down page 3. "Hard to locate battery draw". Check his thread, might be of some help.