Q&A for How to Wire a Car Stereo

You need to look for your car electrical manual. if the manual not available, you have no choice but to trace each wiring. A multimeter may come handy in this task. Head over to professional installer or a friends that may know about it. Car electrical systems can be nasty; never attempt without at least a basic knowledge.

The key wire is for transferring the electronic signals of turning the key fob to the battery, which turns on the rest of the engine.

This likely because you didn't connect to the red ACC wire. That ACC wire is powered only when the key is in the ACC position. The main positive wire (usually a thicker yellow) is directly tapped to your battery. So it is important to connect to the correct wire.

The stereo may not work without it. The red wire is typically the positive power wire, and the stereo requires power to function. If you are referring to a different wire, such as the wire for a specific feature or accessory, it may or may not affect the functionality of the stereo. It would depend on the specific feature or accessory that the wire is connected to. In general, it is important to properly connect all wires when installing a stereo to ensure that it functions correctly and to avoid any potential damage to the stereo or other components.