In automotive electronics, body control module or 'body computer' is a generic term for an
electronic control unit
An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle.
Modern vehic ...
responsible for monitoring and controlling various electronic accessories in a vehicle's body.
Typically in a car the BCM controls the
power windows
Power windows or electric windows are automobile windows which can be raised and lowered by pressing a button or switch, as opposed to using a crank handle.
History
Packard had introduced hydraulic window lifts (power windows) in fall of ...
,
power mirrors
A power side-view mirror (power side mirror, power wing mirror, or simply power mirror) is a side-view mirror equipped with electrical means for vertical and horizontal adjustment from the inside of the automobile.
The glass of a power mirror may ...
,
air conditioning
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
,
immobilizer
An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key (''transponder'' or '' smart key'') is present. This prevents the vehicle from being " ...
system,
central locking
Power door locks (also known as electric door locks or central locking) allow the driver or front passenger to
simultaneously lock or unlock all the doors of an automobile or truck, by pressing a button or flipping a switch.
Power door locks w ...
, etc.
The BCM communicates with other on-board computers via the car's
vehicle bus
A vehicle bus is a specialized internal communications network that interconnects components inside a vehicle (e.g., automobile, bus, train, industrial or agricultural vehicle, ship, or aircraft). In electronics, a bus is simply a device that con ...
, and its main application is controlling load drivers – actuating
relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
s that in turn perform actions in the vehicle such as locking the doors, flashing the
turn signals
The lighting system of a motor vehicle consists of lighting and signalling devices mounted to or integrated into the front, rear, sides, and in some cases the top of a motor vehicle. They illuminate the road ahead for the driver and increase th ...
(in older cars), or dimming the interior lighting.
References
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Automotive Central Body Controller
Automotive electronics