The relay is powered up and activated thanks to a small electrical current. When it is activated, it lets a current that is much bigger than the original one flow through other two outlets. It is used to control the headlights, the rear fog light, the electric fan, etc.
On my 2014 Chev Traverse LTZ, about 1 month ago my low beams stopped working, high beams are alright, running lights are good, tried to replace the hid low beam relay, but it has been discontinued and the dealership has no options. So far my next step is to check both low beam bulbs, which has been the answer for multiple other Chevrolet Traverse owners, apparently there can be a power surge that will stop both low beam bulbs from working at the same time, then once both bulbs were replaced there was no issues, so I'll try that next.