A BCM, or Body Control Module, is an electronic control unit responsible for monitoring and controlling various electronic accessories in a vehicles body. It is a comprehensive system that communicates and integrates the work of all electronic modules through the vehicle bus. The BCM controls the power windows, power mirrors, air conditioning, immobilizer system, central locking, lighting systems, and other comfort and safety features in a car. The BCM communicates with other on-board computers via the cars vehicle bus, and its main application is controlling load drivers – actuating relays that in turn perform actions in the vehicle such as locking the doors, flashing the turn signals (in older cars), or dimming the interior lighting. The BCM is a microprocessor-based unit that uses software to control the various functions its responsible for. It receives input from sensors and sends signals to output devices based on this data. The BCM also communicates with other Electronic Control Units (ECUs) in the vehicle through communication interfaces such as the Controller Area Network (CAN) or Local Interconnect Network (LIN) .