When majority refers to a particular number of votes, it takes a singular verb:Her majority was five votes. His majority has been gorwing by 5 percent every year.
When it refers to a group of people or things that are in the majority, it may take either a singular or plural verb, depending on whether the group is considered as a whole or as a set of people considered individually.
So we say The majority elects (not elect) the candidate it wants (not they want), since the election is accomplished by the group as a whole; but The majority of the voters live (not lives) in the city, since living in the city is something that each voter does individually.