When it get dark , it will turn on the width light and headlight automatically ( only control the low beam) .This sensor control by two stages . When it start getting dark , the width light will turn on firstly , when it become darker , then the headlight turn on . When day break , both headlight and width light turn off automatically .When the car getting through a tunnel , the light will turn on . exit the tunnel , light off Leaving home and coming home function.Fit for below vehicles:For Aveo 2012For Cruze 2010 2011 2012 2013For Opel j 2012 2013 2014 2015 2016 2017 2018 2019The module is directly connected between the original car switch and the wiring harness.Install :White connect to +12V(Only when the key is in or ON state can output)Red connect to +12V (This is the battery 12V, no matter what the state of the key, there is output)Warm tip: Use fuse box cap or multimeter to find these position.Colour: blackMaterial: ABSPackage Contents:1 x Headlight Switch Control Module SensorOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.