Chime and Data-bus Integration Module for select late model GM Class-2 data systems with the 24-Pin dock-n-lock connector without OnStar or Premium BOSE sound system. The GMCO3 decodes chime signal commands on the Class-2 data-bus and supplies the appropriate warning tone from its built-in speaker. The GMCO3 is the perfect solution for any GM vehicle without OnStar that utilizes Class-2 commands to produce seatbelt, key in ignition or headlight warning chimes.