Rewiring your car and bypassing the computer can be an intimidating task for a beginner mechanic like myself. However, with some persistence and the right tools, I was able to successfully rewire my 1996 Honda Civic and bypass all of the computer components for free.
In this article, I will walk through the step-by-step process I followed to rewire my Honda Civic in order to bypass the computer. I found this allowed me to simplify the wiring harness, eliminate unnecessary computer components, and give me more direct control over all of the electrical systems.
While this process does require some mechanical skills and knowledge, it can be done by any determined do-it-yourselfer without having to pay a professional mechanic. I will focus on covering the essential information you need to know in order to successfully rewire your own vehicle computer-free.
Gather the Necessary Tools and Materials
Before getting started, you will want to make sure you have the proper tools and materials on hand. At a minimum, you will need:
- Wire strippers - for removing insulation from wires
- Crimp connectors - for connecting wires together
- Electrical tape - for insulating connections
- Multimeter - for testing circuits
- Wiring diagram - showing how the factory wiring runs
- Assorted wiring - for splicing new wires as needed
I also found it very helpful to have a soldering iron, heat shrink tubing, zip ties, and an assortment of fuses/fuse holders. Having these extra tools and supplies made the rewiring process much simpler.
Create a Game Plan
Once you have all of your supplies ready, it is time to come up with a plan of attack. I recommend getting a wiring diagram for your specific make and model vehicle. This will show you how the factory wiring is laid out and will help you understand what connections need to be made.
Carefully study the diagram and determine what wiring harnesses/components you want to remove or bypass. For me, I decided to bypass the entire computer system and simplify the wiring down to just the essentials needed to run the engine, lights, gauges, etc.
Before starting any work, be sure to disconnect the negative battery cable. Working with live circuits can be extremely dangerous, so always disconnected the battery as a precaution. You will want to keep it disconnected throughout the entire rewiring process.
I also recommend having a fire extinguisher handy, just in case an electrical fire were to break out while working on wiring. Be sure to take all necessary safety precautions - better safe than sorry!
Removing the Factory Wiring
With your game plan in place and safety gear at the ready, it's time to dive into the teardown. This step will involve removing the majority of factory wiring from the vehicle.
Take It Slow and Label Everything
I can't stress enough how important it is to take this process slowly and be organized. Remove connectors one at a time, labeling each wire as you disconnect it. I used small pieces of tape with wire numbers written on them. This keeps everything organized so you know exactly where each wire runs when it comes time to rewire.
Cutting Out Unnecessary Wiring
According to the wiring diagram, I identified all of the wiring that connected to modules and components I was removing - engine computer, AC system, air bags, etc. I carefully cut out and removed any wiring that was not needed, saving only the essential wiring for the engine, drivetrain, lighting, gauges, etc.
Again, having the diagram makes this process smooth since you can trace exactly what each wire does. Refer back to your game plan and remove only what you have decided to eliminate. I recommend removing a little at a time to be safe.
Rewiring the Essentials
With all of the unnecessary factory wiring removed, it was time to begin rewiring the essential systems I wanted to keep.
Start With One System At a Time
I found it best to start with one system at a time - for example, rewiring just the engine first. I would get the essential engine wires reconnected before moving onto the next system. Here are the essential systems I rewired:
- Engine - spark plugs, fuel pump, alternator
- Gauges - oil pressure, coolant temp, voltage gauge
- Lights - headlights, brake lights, turn signals
- Ignition switch - starter motor, accessory power
Use Proper Connections
When splicing into the existing wiring, it is critical to use proper crimp connectors or solder. Do not just twist wires together with tape - this can lead to shorts or loose connections. Take your time and make each connection properly.
I also recommend using fuses for any added wiring to protect from shorts. Test each circuit with a multimeter before moving to the next system.
Once all systems are properly rewired, there are just a few finishing steps:
Secure and Organize Wires
Use zip ties and wire loom to neatly secure and organize the new simplified wiring harness. This helps protect the wires from damage.
Insulate Exposed Connections
Make sure any exposed wire or connections are fully insulated with heat shrink or electrical tape. This prevents wires from shorting out.
Reconnect Battery and Test
Finally, with everything buttoned up, reconnect the battery and test all systems. Make sure lights, engine, gauges etc are functioning properly before taking it for a test drive.
Hitting the Open Road Computer-Free
After completing the rewiring process on my Honda Civic, I was thrilled to hit the open road in my simplified, computer-free ride.
I did run into a couple small issues with lights not working properly. But with my simplified wiring, it was easy to troubleshoot and fix these bugs - no complex computer to decode!
Rewarding Do-It-Yourself Project
While not an easy task, rewiring your vehicle computer-free is an extremely rewarding DIY project for any hands-on automotive enthusiast. I gained so much knowledge about the inner workings of my car.
Added Control and Reliability
Bypassing all the unnecessary factory computer modules resulted in a more reliable and easily repairable system. I don't have to worry about complex electrical issues or throwing mysterious computer codes. I now have full control over each system.
So if you're up for the challenge, I highly recommend taking on this do-it-yourself rewiring project. The ability to customize and simplify your car's wiring is incredibly empowering. Just make sure to be safe, take your time, and enjoy the ride!