Is the 2 way wire going to alternator supposed to read a constant voltage?

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! The two-way wire going to your 2020 Dodge Charger’s alternator (which typically includes a voltage sense wire and a control wire) should have a stable voltage reading. If the voltage on the positive wire is fluctuating drastically, that’s a sign there may be an issue with the voltage regulation. Since you’ve already replaced the alternator, battery, and sensor, the problem might be in the wiring or the engine control module (ECM), which controls the alternator output. Check for any loose or corroded connections, especially at the battery terminals and ground points. A bad ground can cause erratic voltage readings. Also, inspect the harness going to the alternator for any damage or shorts. If the problem persists, it could be a deeper ECM issue that requires further diagnostic testing. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.