I have 1991 dodge Dakota v8 318 5.2L which is giving me a charging problem. I replaced the alternator and battery for quick fix but still can't keep a charged battery. Voltage regulator is within the vehicle computer and I'm getting a engine code 12. Should I get a new computer? (SMEC)

Possible causes-- Low battery charge
- Battery defective
- Loose or missing alternator drive belt
- Faulty alternator
- Open or short system voltage circuit

Start by checking battery voltage.

When you replaced the alternator, did you also replace the voltage regulator? I have read that on this truck, the voltage regulator is internal to the ECU and is located on the firewall near the ignition coil. You may be able to install a separate, dedicated voltage regulator available at your local auto parts store. Please note that you may have to rewire from the ECU connector to the stand-alone voltage regulator. Good luck.

you need to check you battery chances are it needs to be replaced most battery shops can check for you. if your battery is old it may have one or several bad cells and will not hold a charge. also could be a short that is draining battery while car is off

1997 DODGE DAKOTA CHARGING SYSTEM
OPERATION:
The amount of amperage produced by the alternator is controlled by the Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM)
EVR circuitry is connected in series with the alternator field driver terminal and ground. A Battery Temperature Sensor (BTS), located in the battey tray under the battery, is used to sense battery temperature.
Sensed battery temperature and data from monitored line voltage is used by the PCM to adjust the battery charging rate. This is accomplished by cycling the ground path to control the strenght of the alternator magnetic field.
The PCM then compensates and regulates alternator amperage output accordingly.
If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM memory and the Malfunction Indicator Light (MIL) (commonly refered to as the "check engine light") will be illuminated, providing certain criteria have been met.
DTCs can be read using Chrysler's Diagnostic Readout Box (DRB-III) or a generic scan tool.
When diagnosing any problem concerning the charging system on this vehicle, it is recommended that you begin by scanning the PCM for fault codes in order to eliminate certain possibilities and provide a more accurate and timely diagnosis.
If you have any fault codes pertaining to your charging system, please post them in a reply on this page and I will be happy to guide you through the diagnosis process.

Check output from alternator with a voltmeter it should be between 13.8 to 14.7 if so then check at battery if it is not at least 13.8 minimum to be charging then the big wire on back of alternator is not getting back to the battery through ammeter gauge in dash.
I have hooked a wire from back of alternator straight to the plus[+] side of battery to fix that issue.
Sometimes ammeter gauge burns out breaking the circuit from the alternator back to the battery.

There are a few things you can check. There should be a large fuse in the fuse box in the engine compartment. I believe it is a 100amp fuse. If you connect the jumper cables backwards or even touch the wrong post for a split second it can cause that fuse to blow. Also check the connector on the back of the alternator they sometimes are dirty or have a bad connection in the plug also check to make sure the connectors are not open and are making good contact. Do yourself a favor and check all the fuses inside the cab and in the engine compartment. Good luck and let me know if this fixes it, if not I will research it. I will look for your reply over the next few days

If you need further help, I’m available over the phone at https://www.6ya.com/expert/edward_020b3320326d263d

It sounds like the alternator needs to be replaced. To be sure, take the alternator off and take it to a local parts store and they will check it for free. If you replaced the battery, then it just isn't charging. Try the alternator first, and let me know how that works.

could be that the alternator is not getting any voltage to energize the field. also could be an issue with cables between the battery and the alternator. just a couple of things to check.

az alts arnt the best. the volt reg in the ecm. you need to have it tested

I was running into this problem with my 97 5.2l Dakota and after some searching I found the the "Fuse Link" between the Alternator and the Battery was blow. Found a suitable "Fuse Link" at a local Auto parts store for about $5.