I have a 2012 Dodge Grand Caravan with the 3.6 pentastar. I have the battery light on on my dash and with my scan Guage connected to the obd2 connector inside the van it's showing 12.3 with the van running and slower drops lower and lower as the van is running. When I put a load on it it droppes to 11.8 volts. I fully charged the battery and it showed 12.4 volts when I started it. I am thinking that the alternator is on its way out. Any tips would be great. Thank you

Your charging system is not working correctly. Unlike most other vehicles, the alternator in yours does not have a built in regulator circuit. Some troubleshooting must be done to find the defective component. Most of this can be done with the vehicle still assembled.

First, check that you don't have a blown fusible link. In most newer cars, these will be in the underhood fuse panel, and look like giant fuses. If good, you will read very nearly zero volts and zero ohms when measuring between the positive battery terminal and the alternator output terminal. If either measurement doesn't read zero, find the loose connection, bad wire, or blown fusible link.

Next, check the ground connections to the engine, battery, and car body to make sure you don't have a bad wire or connection somewhere. Again, measure voltage and resistance between the negative battery terminal and all associated grounding locations. For a quickie test, you can rig a jumper cable between the battery negative terminal and the alternator case. If there is a spark when you make the connection, you have a bad ground somewhere.

If your battery is well connected to the alternator, the problem may lie in the control circuit. Most Chrysler alternators have two control wires that control the field coil. Some control the battery current and have constant ground supplied, and some have battery voltage applied and control the ground current. To test, disconnect the control connector and measure the voltage of both terminals with the ignition in the "off" and "run" positions. Make a chart of each terminal and its corresponding voltage.

Start the vehicle and measure both terminals again. If the terminals tend to be zero volts, except when the vehicle runs you have voltage on one terminal, you have a system where the computer controls battery voltage. If the terminals tend to be 12 volts when the ignition is on, then one terminal goes low when the engine runs, the computer controls ground current. If the voltages of one terminal change but not the other, this suggests a bad computer.

To do a go/no go test of the alternator unit, you can connect the control pins on the alternator with the control connector disconnected. Simply connect jumper wires to the two control terminals of the alternator. Connect one jumper to a known good ground, leaving the other jumper loose. Connect a voltmeter to the battery terminals or to the output wire on the alternator. Start the vehicle and briefly connect the second jumper wire to the positive battery terminal while watching the voltmeter. While the jumpers are both connected, the battery voltage should rise dramatically.If it doesn't, this suggests a bad alternator.

If all this sounds too complicated or dangerous, a good mechanic can perform a similar diagnosis in under an hour with definite results. Good luck.

Disconnect the positive wire on battery..if still runs alternator good....if it dies then its bad