Battery not charging?

MADIP1996

MEMBER
2010 DODGE RAM
140,000 MILES

Battery drained out, we got a jump and made it home (about 7-10 miles) if acceleration was kept charging battery. Next day barely went five miles and it shut off completely. I bought three alternators and two batteries. There is a drain still even when it's turned on and revved up. Not charging battery or battery drain so intense it can't charge fast enough. TPMS sensor light on none of TPMS sensors or module is showing nearly the mhz it's supposed to. Checked all ground wiring and wiring harness for damage or frays, nothing. Checked fuse box, cleaned it and replaced all fuses, still didn't fix it. Checked all lights on and in the vehicle to make sure they weren't staying on, they weren't. Nothing stays on after the vehicle is turned off. Battery drains only when turned on and run. Battery charged fine (sometimes cables get hot if from one vehicle to trucks battery). The amp wiring has been removed. New terminals put on. Radio unplugged and removed. Friend brought and used an Autel reader showed everything working fine accept alternator not sending charge to battery. It didn't show any cause for it all sensors are tightly plugged and no bad wiring. All spark plugs are in good standing. The belt is in perfect condition. Spindles are in perfect condition and evenly placed on. I don't know what else it could be. Why won't it charge the battery?

Monday, September 5th, 2022 AT 8:38 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

If I can ask, what brand rebuilt alternator did you use? The alternator is controlled by the PCM so this may be an issue. Here are the alternator wiring diagrams so you can see how the charging system works. Also, when you did the scan was it a CAN scan? This kind of scan is easy to do. You can get a CAN (controller area network) scanner from Amazon for about $30.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is a scanner link:

https://amzn.to/3o41KcZ

It can tell you if the cluster is bad which could be a possibility as well. Do me a favor and rest your hand on the TIPM to see if this is shorted which is common and easy to replace because it-self learns. You can see it interrupts the alternator wiring.

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