How to Wire Car Radio (Full Diagram)

▶ Try it free in your browser: https://circuitdiagrammaker.app/try?utm_so... How to wire a car radio — the full head-unit harness, free in your browser: https://circuitdiagrammaker.app/try?utm_so... A car radio harness looks like a spaghetti of colours, but every wire has a known colour and exactly one job. This tutorial takes a finished car-radio wiring diagram apart wire by wire, so the whole loom finally makes sense — and you can open the same diagram free, with no install and no signup. We start with power, because that is where people get it wrong. The YELLOW wire is constant twelve volts, straight off the battery — it never switches off, and it is what keeps your clock and presets alive. The RED wire is switched, the accessory (ACC) feed — it only goes live with the key, and it powers the radio up. Swap those two and the radio forgets every station the moment you switch off. Then BLACK to ground, on clean bare metal. From there: the ORANGE illumination wire that dims the display with your dash lights, and the thin BLUE remote turn-on that tells an amp or a power antenna to switch on with the radio. Then the four speaker pairs — front-left, front-right, rear-left and rear-right — each with its own plus and minus, with the two rules that matter: never ground a speaker negative, and keep polarity straight so the bass does not cancel out. We finish with the painless way to fit an aftermarket radio: a harness adapter that clips into your car's factory plug so you never cut the original loom, and how to add an amp with its own battery feed, an RCA signal pair, and the blue remote wire. Full disclosure, said plainly in the video: CircuitDiagramMaker is our tool. It is genuinely good for clean, shareable wiring drawings you can mark up and hand off, and PNG export is free. The guest editor ships the free do-it-yourself symbol pack, which is what the live build uses. This is an honest, testable walkthrough of how to wire a car radio, and you can check every claim yourself in about ten seconds. Safety: disconnect the battery before you work behind the dash, and never ground a speaker negative. Sources & further reading: https://circuitdiagrammaker.app/diagrams/c... https://circuitdiagrammaker.app/blog/car-s... https://circuitdiagrammaker.app/blog/speak... https://circuitdiagrammaker.app/diagrams?u... https://circuitdiagrammaker.app/symbols?ut... — Chapters — 0:00 The finished car-radio diagram 0:22 What a head-unit harness is 1:05 Draw along free in your browser 1:20 Power: yellow constant, red switched, black ground 2:20 Illumination + the blue remote turn-on 3:05 Four speaker pairs + polarity 4:00 Aftermarket harness adapter — no cutting 4:45 Adding an amp: remote wire + RCA 5:30 A real car-stereo wiring diagram 6:00 Building a harness live 6:40 Export your drawing 7:15 Troubleshooting: lost presets 7:45 Recap — wire your car radio free #caraudio #carstereo #headunit