Sec. 3. (a) The legislative body of a unit (other than a township) may, by ordinance, establish a merit system under this chapter for the police or fire department of the unit. The legislative body of a township may, by resolution, establish a merit system under this chapter for the township's fire department. Before the merit system takes effect, however, the system must be approved by a majority of the active members of the department in a referendum.
(b) The legislative body shall specify in the adopting ordinance or resolution which of the provisions of this chapter that are left to its discretion are being adopted.
(c) If a merit system is established under this chapter for each department of a unit, each department has a separate merit system.