A wire harness is the collection of wires used to hook up the head unit of a car stereo to the speakers, antennas and power source. These wires are color-coded according to their purpose.
A stereo's head unit is the control panel of the system. The screen, buttons, volume control and CD or cassette player (depending on the model) are all part of the head unit.
For wiring and installation purposes, color coding is often used because it simplifies the process of matching wires to their proper uses. Each wire is a different color according to its function, preventing any confusion or misuse.
In a standard head unit wire harness, there are 14 colors used. Yellow stands for memory, red for switch/accessory, black for ground, orange/white for illumination, blue for antenna remote, blue/white for amp remote, white for left front speaker (+), white/black for left front speaker (-), gray for right front speaker (+), gray/black for right front speaker (-), green for left rear speaker (+), green/black for left rear speaker (-), violet for right rear speaker (+) and violet/black for right rear speaker (-).
