The 12 volt constant power wire is usually yellow or blue though it may be a number of colors coming from the car. These same 3 wires will need locating on the car loom now and im going to assume that you have a meter of some description that can read dc voltage in the range of 0 20vdc.
1 0 Awg Car Audio Ground Cable 0 Gauge Power Cable Wire Buy
Car audio ground wire. If there is no ground wire you can secure the ground cable to bare metal in the body of the car to serve as a ground. The one that shows continuity is your ground and you can move on. Cables are some of the most important components in a car audio system because they ensure that a sufficient amount of power gets to the amp the proper signal is transferred and that the overall system can function properly. You just have to connect the ohmmeter to a known good ground and then check each of the wires in the car stereo harness for continuity. If for some reason your current stereo was not grounded through a wire the diagram on the back of the wiring adapter kit will tell you you can ground the car stereo by finding a screw under there to which this wire can be attached. For each amplifier in the system having the same gauge of wire is absolutely necessary.
In order to connect your car audio components you will need power and ground cable. Car radios tend to use a red and yellow wire for the permanent 12v and a black wire for 0v earth but again the radio manual will be more specific. The ground wire for the stereo will be black as will its corresponding wire from the car. Interconnect rca signal cables powerground wire and speaker wire can be found in here in a variety of sizes colors and lengths. Cables wire adapters connectors. The ground cable completes the electrical circuit and is connected to the vehicles chassis.
If your car is like most and has a ground wire for the car stereo already just cut the connector off and crimp it to the adapter harness. The power cable transfers the electrical current from the vehicles battery to the aftermarket amplifier. If you cant locate the ground wire visually then the best way to locate the ground wire is with an ohmmeter.