Mich. Comp. Laws § 730.505

Sec. 5. All justices of the peace whose courts are affected by this act are hereby constituted judges of the municipal court of the city wherein they were severally justices of the peace immediately prior to the taking effect of this act and shall hold office for the remainder of the respective terms for which they were elected justices of the peace. Whenever a vacancy shall occur in the office of any judge of such court by death, resignation, removal from office or from any other cause, such vacancy shall be filled in the same manner as heretofore under the provisions of the respective city charters or the general laws of this state.