ride height sensor!?

so i took my 06 530i to a local dealership to get detailed and front end alignment.... so they called me and told me my front ride height sensor is out? and they wanted to fix it for 250$. i like to do this kind of stuff myself so i said no and picked it up. i cant find any parts online called a ride height sensor? only headlight level sensor! can someone clear up all this confusion? thanks in advance!