Do you need wiring harness car stereo?

If your vehicle has (or once had) a factory stereo, or if it was pre-wired with a stereo prep package, there should be at least one plastic wiring harness behind the stereo opening. This plug connects the stereo to your vehicles electrical system and the speakers.

Where do you connect the yellow wire on a car stereo?

1:367:53Car Stereo Wiring Explained In Detail - YouTubeYouTube

Whats the yellow wire for on a car stereo?

The yellow wire is the 12 volt battery wire, which should also be attached to the stereo for power. The final wire, the black wire, is the ground wire. This wire, once attached to the stereo, will help ground it.