How to Rewire Your 20 Year Old Car and Save Thousands


Rewiring an older car can seem daunting, but it is very doable for the DIY mechanic and can save thousands of dollars in labor costs. With some basic tools, patience, and by following proper safety procedures, I was able to completely rewire my 20 year old Honda and give it new life. In this guide, I'll walk through the whole process step-by-step.

Reasons to Rewire an Older Vehicle

There are several good reasons to rewire an older car:


Successful wiring jobs start with good preparation:

Removing the Old Wiring

With the battery disconnected, I started removing the old wiring:

Building the New Wiring Harness

The most time consuming but important step is constructing the new harness:

Installing the New Wiring Harness

Once construction is complete, I installed the new harness:

Testing and Verifying Circuits

With the harness fully installed, thorough testing is key:

Troubleshooting Problems

If issues come up, here is how to troubleshoot:


While rewiring an older car is very involved, it is a manageable project for any motivated DIYer. The job requires methodical planning, patience during construction, diligent testing, and attention to safety. But it could save you thousands in shop fees while adding tremendous value and life to your vehicle. With research and care, you can handle this project!