If you receive a light warning message on your dash or on board computer, or have flickering of your LED headlights, you will likely need this decoder. This is the solution for many German vehicles, pulse width modulated headlight circuits, and some Toyota high beam applications. Recommended at time of installation for most German vehicles and Chrysler/Dodge/Jeep/Ram vehicles after 2007. Some specific applications will also require a resistor. These are offered in corresponding styles to our headlight models and are a simple plug in connection.