The fact that the battery and alternator are okay means you have what is called a parasitic draw. That means something is staying on when it shouldn't.
Here is a guide on the common causes of this issue:
https://www.2carpros.com/articles/car-battery-dead-overnight
If none of this is the cause of the issue then we need need to do an actual ignition off draw test. The way to do this is unhook the negative battery cable and set you meter to amps. Then connect one lead to the cable and the other to the negative battery post. This will display the ignition off draw amperage. It should be around 20 milliamps or less. If it is more then you need to unhook fuses until it drops to this level. Once you remove the fuse that does this then that system is the issue.
At that point, hook the fuse back in and remove the actual components. So for example, you remove the radio fuse and the voltage meter drops, then you find everything that is on that fuse and unhook them one at a time until it drops. Then you know the specific component that is not shutting off. We can help with this point once we know what fuse it is. However, using the battery gauge on the dash is not a proper way of doing it and will lead you down the wrong path.
Please let me know if you have questions. Thanks
Monday, April 20th, 2020 AT 4:57 PM