So you bought yourself an Advanced Gauge Display monitor to help improve engine performance for your GM 6.6L Duramax LML, but to make it work you need one little part that’s easy to forget: the AGD switch cable from aFe. The cable plugs directly into your ECU and the OBDII plug on your monitor so you can seamlessly switch between different settings of EFI-multi-position tunes on your drive directly on your monitor. Equip your Duramax with some added horsepower and the ability to flip through tunes on the fly with your DSP5 switch, all connected with this AGD cable from aFe.