Improving the sound quality of your car stereo can make a world of difference in your driving experience. While upgrading to new speakers or amplifiers can help, rewiring your car's existing stereo system is an effective way to get cleaner, louder sound without replacing components. In this guide, I'll walk you through the complete process of rewiring a car stereo from start to finish.
Gather the Necessary Tools and Materials
Before getting started, you'll need to assemble the proper tools and supplies. Here's what you'll need:
- Wire strippers - to strip away insulation on wires
- Crimping tool and terminals - to attach connector terminals to wires
- Soldering iron and solder - for soldering wires
- Electrical tape - to insulate wired connections
- Cable ties - to secure and organize wiring
- Multimeter - to test connections
- Upgrade wiring kit - contains thicker power/ground wires and connectors
I recommend using a basic upgrade wiring kit designed specifically for car audio. This will provide thicker power and ground cables to deliver increased current.
Disconnect and Remove the Factory Wiring
With your tools gathered, it's time to dive into the wiring. First, disconnect your car battery to avoid electrical shorts.
Next, you'll want to remove any panels or trim pieces necessary to access the back of the car stereo and existing wiring. Use proper pry tools and work slowly to avoid breaking plastic clips or brackets.
Once you can see the rear of the stereo, disconnect all existing connectors and cut or unbolt the factory wiring harness. Be sure to take note of each wire's function (ground, power, speaker channels, etc) as you remove them.
Install New Power and Ground Wiring
One of the main goals of rewiring is to use thicker power and ground cables that can handle increased electrical loads.
Run the new power cable from the stereo's power terminal to the positive +12V terminal on the car battery or other source of constant 12V power. Use crimp connectors or solder to fasten the end of the wire securely.
Do the same process to connect the thicker ground wire from the stereo to a metal grounding point like a seat bolt or the vehicle chassis.
Make sure both power and ground connections are solid. Insulate connections with electrical tape and secure wires with cable ties to protect them from vibration.
Connect Accessory Switched Power
In addition to constant battery power, your stereo will need switched +12V power that energizes only when the ignition is turned on.
Splice the new accessory wire into an existing ignition-switched wire under the dash, often from the fuse box. Use a voltmeter to confirm you have ~12V only when ignition is on.
Run New Speaker Wires
The speaker wiring bundled with factory harnesses is often thin and prone to power loss.
Run fresh speaker wires from each speaker terminal on the back of the stereo to the corresponding speaker. Use proper speaker wire, ensuring you have conductor pairs with both left and right channels.
Carefully organize and route the new speaker wires cleanly through the dash and down the doors. Cut each wire to length and terminate with crimp clips or solder to connect to each speaker.
Test New Connections and Reinstall
Before bolting everything back in place, test operation of the rewired system. Turn the car ignition on and confirm stereo powers up and speakers output audio.
Check for stereo operation on different volume levels to ensure the wiring can handle higher loads without cutting out.
Once functionality is verified, securely mount the stereo, reconnect trim panels, and enjoy your rewired car stereo and improved audio quality!
FAQs About Car Stereo Rewiring
Here are some common questions about rewiring car stereos:
What gauge wires should I use?
For power and ground, 4 gauge or 6 gauge wires are recommended for most stereos. For speaker wires, 16 or 18 gauge wires will work well.
Where do I connect the ground wire?
Look for bare metal spots with paint removed like seat bolts, or sand a spot for grounding. Chassis metal usually works well.
Do I need to upgrade my fuse?
Yes, when adding thicker power cables, it's wise to upgrade to a higher amp fuse protecting the circuit to match the amp capacity of the new wires.
Is soldering or crimping wires better?
Either method works fine if done properly, but soldering provides the most robust, low-resistance connections. Use heat shrink to insulate.
With quality materials, proper wiring techniques, and safe installation, rewiring your car stereo on your own can lead to significant improvements in sound. Just take it slow and be cautious when working with automotive electrical systems.