Wire identification charts are used to identify the vehicle's factory audio wiring to repair damaged wiring or connections or to attach a wiring harness designed to plug into an aftermarket radio. In order to properly identify the factory audio wiring, it is necessary to obtain a wiring diagram for the year, make and model of the vehicle.
Factory wiring colors and information can be found in manufacturers' maintenance guides for most vehicles. If there is no power or intermittent power to the radio, power but no sound, or static coming from all speakers, a loose connection or worn wire on the radio's input harness is a possible cause of the problem. If no sound is coming from certain speakers but is coming from others, the problem is likely to be the wires that output from the radio to that speaker. Use a wiring diagram to identify the wires and connections causing the malfunction. If all connections are inspected and no problem is found, the radio could be malfunctioning.
Aftermarket car stereo head units' wires have standard colors for most brands across the industry. To simplify the installation process for a car stereo installation performed at home, many companies produce installation kits featuring mounting hardware, replacement dash upholstery and detailed instructions with diagrams. For some vehicles and stereos, special wiring harnesses are made to easily connect to factory harnesses without having to worry about matching colors, enabling the installer to avoid cutting and splicing wires.