Where is the ECU Located in a Dodge Dakota

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.

You about have to have a bad alternator or battery. What does your amp gauge say when you are driving down the road and have your lights on? Does it show that the battery is taking a heavy charge? Did you put a ohm meter set to DC current on your battery when it is running to see if the alternator is putting out?

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.

Check the battery for a defective cell.. You should replace the battery
to check
remove all the top up caps from the battery
start the vehicle and look for fumes rising from the cell

also check the electrolyte in the battery making sure alll the cells are covered.
,,,

or

the alternator is charging.
to test this start the vehicle and remove the positive battery pole, the car should remaing running, if it cuts off your alternator isnt charging,