Modular light bar messaging system

Techniques for communicating lighting commands through a controller area network (CAN) bus of a light bar system include generating a light code message. The light code message has a metadata portion and a value portion. The metadata portion defines a purpose of value portion. The value portion controls a state of a lighting device (e.g., a keypad's LED brightness or activation of a directional light module) in the light bar system. A data field is generated by encapsulating the light code message with an ISO-TP single frame header and a message subtype. A CAN controller generates a CAN message having an extended frame format and the data field. The CAN message is then transmitted through the CAN bus.