Rewiring your car's electrical system may sound daunting, but it can actually be done quite easily and inexpensively if you follow some simple steps. In this guide, I will walk you through everything I've learned from successfully rewiring my own car's electrical system for under $50.
Reasons To Rewire Your Car's Electrical System
There are a few key reasons why you may want to rewire your car's electrical system:
Upgrading Your Stereo
If you want to upgrade your factory car stereo to an aftermarket one with more wattage, you'll likely need to rewire the stereo system to handle the extra power. The factory wiring is usually too thin to handle aftermarket stereo amps.
Over time, the electrical wires in your car can become damaged or corroded. Rewiring allows you to replace old brittle wiring with brand new wires.
Added Electronic Accessories
If you've added a lot of electrical accessories like lights, inverters, or cameras to your car, a rewire ensures your electrical systems can handle the extra load.
Choosing the Right Gauge Wire
The wire gauge (thickness) you choose depends on the amount of power in your car's electrical system.
For most standard factory electrical systems, 16 or 14 gauge wire will be sufficient. This can handle up to 40-60 amps.
If you've added a high-powered stereo or have a lot of accessories, you may want to go with 12 or 10 gauge for up to 80-100 amps.
For race cars or very high-end audio systems with over 500 watts, 4 or 0 gauge thick wire is recommended.
Rewiring your car's electrical system involves dealing with live wires, so safety is paramount:
Wear insulated gloves to protect yourself from electrocution.
Always disconnect the negative terminal of the battery first before doing any work.
Only work on one circuit at a time and disconnect power from other circuits to prevent overload.
Avoid shorts by taping up wire ends or capping them with wire nuts.
Have a fire extinguisher nearby just in case.
Follow these steps to rewire your car's electrical system:
1. Plan The Wiring Layout
Make a diagram of where all the wires will run and what components they will connect.
Plan where you'll mount things like fuses, distribution blocks, and relays.
Measure the length of wire needed for each connection.
2. Gather The Needed Supplies
For a full rewire, you'll need:
- Wires in various gauges
- Loom for wrapping wires
- Crimp connectors and terminals
- Fuses, fuse holders, relay(s)
- Distribution block(s)
- Wire stripper & crimper
- Electrical tape
- Zip ties
3. Remove The Interior Panels
- Take out seats and carpet to access the floor.
- Remove trim panels to expose wiring paths.
4. Run New Wires
- Route the new wires through the paths you've opened up.
- Keep wires neatly bundled.
- Allow extra length in case you need to change something.
5. Connect Wires To Components
- Cut wires to length and strip the ends.
- Crimp on appropriate terminals and connectors.
- Connect wires to components like lights and amplifiers.
6. Install Protection Devices
- Put in-line fuses on each circuit for overload protection.
- Connect relays and distribution blocks as needed.
7. Test The System
- Reconnect the battery and test all circuits one by one.
- Check for loose connections and shorts.
8. Complete The Install
- Bundle up excess wire with loom and zip ties.
- Refit all interior trim panels.
- Test again to make sure everything is working properly.
And that's it! With the right planning and safety precautions, you can rewire your car's electrical system in a weekend for less than $50. Taking the time to do a full rewire will provide you with clean reliable power for all your car's electronics.
How do I know what gauge wire to use?
Choose wire that is rated for at least 20% more amperage than your system requires as a safety margin. For most cars, 16 or 14 gauge is sufficient.
Where do I connect the new wires to?
Connect your new wires directly to the battery, alternator, and grounding points. Install relays, fuses, and distribution blocks to split power to the various circuits.
What are the signs my wiring needs to be replaced?
Dimming headlights, electrical shorts, failed fuses, and flickering dash lights can indicate old brittle wiring that needs replacement.
Can I leave my factory wiring in place and just run new wires?
It's generally better to do a full rewire, but you can run additional wires if needed by routing them away from factory wires.
Rewiring your car's electrical system might seem intimidating, but as you can see it can be done with a little preparation. Not only will you save money by doing it yourself, but you'll also end up with a clean electrical system that meets all your car's needs.