what the hell is that little box with a green flashing light on it? its under the drivers side, below the steering wheel. It was not plugged in, so i plugged it in and it showed a flashing green light. it also has a button on it that im not sure what the function is. please help me identify this thing.

 

Welcome to the forum, vramirez!

Which model year and type of engine does your Avenger have? Also, is your vehicle stock or are there aftermarket parts installed?