Automotive upgrades are a big part of our hobby. Every car enthusiast enjoys making changes to their pride and joy, those personal touches that individualize the vehicle to the owner. Many of these upgrades turn out to be electrical accessories, which puts a burden on factory wiring. Especially original factory wiring that is 40 years old or more.

Many car enthusiasts tend to overlook a vehicle’s electrical wiring or simply avoid the idea of re-wiring their car because of the intimidation factor. An old or poorly done wiring job won’t let the electrical accessories work properly or to their full potential. In addition to poor performance, an aging and out of date wiring system may be unsafe. We reached out to Scot Bowers at Ron Francis Wiring for some tips on how to properly re-wire a vehicle without worrying. “It is always a good idea that the installer is also the owner/driver. They will learn from the install and if there is trouble down the road, they will be more familiar with how the electrical system is done.”

For most jobs that a home builder takes on, a common set of hand tools is usually good enough. Doing electrical work requires a few specialty tools to do the task correctly. A good set of wire strippers that remove the wire’s insulation without cutting into the wire and a good wire crimper with terminal dies for the wire terminals and connectors you will be using.

Other electrical tools that you may want to keep in your toolbox include a soldering iron with solder that has rosin core flux, a wire brush, a volt/ohm meter, test light, electrical tape,and shrink tubing. These will come in handy and make the job look professional.

When it comes to wiring, the three basic factors for consideration are wire size and material type, and color. According to Bowers, the wiring kits at Ron Francis simplify all those choices and all you have to worry about is picking a front loading or pre-wired fuse panel. “This simply refers to the fuse box choice and direction of the wiring process,” said Bowers. “With the front loading design you mount the panel, then run to wires toward the panel, connect the component, then you cut to length, terminate and attach it to the panel.” This has been the common method of wiring with kits for decades.

Planning out the wiring in simple diagrams can take much of the confusion and fear away from the project.

When it comes to simplicity, the Ron Francis pre-wired fuse panels make things even easier. “With the Pre-wired design, the harness is already pre-wired, coming out of the fuse box, which you mount, then run the wires out toward the components they will attach to, trimming them depending on which series you are installing,” added Bowers. “It is important to wire a car by circuits, this way you can stop and start as time permits with little confusion.” We also noticed that the Ron Francis fuse box kits are bagged so that the installer can wire one circuit at a time.

With the wire size, material, and wire color issues taken care of, there is no need to worry about current draw or voltage drop. Stranded copper wire for conductivity with flexibility for routing, and proper color coding for your manufacturer. The biggest factor left in planning is how many circuits will you be running? This is an important concern if you plan on adding more accessories later. You need to leave room for expansion.

Start with the fusebox. According to Bowers, the most logical place to install the fusebox is in the front left corner, the wires are physically shorter. The steering column, dash gauges, dimmer and headlight switches and other driver controls and switches are right there. This means shorter wires resulting in less voltage loss (AKA:resistance).

When planning your circuits, keep this pro tip in mind: Pro Tip #1: You can have too many fuses. Never connect one item to more than one fuse. When it comes time to plan your wire routing, Bower’s offered a couple more fundamental tips. “Lower and shorter is better. We don’t recommend routing wires through headliners because they chaff inside door posts, tend to be difficult to troubleshoot, and lengthens the wire too much,” he stated. “Shorter wires offer less resistance and pose less risk of physical damage.” Besides, shorter wires offer less weight and space and are easier to conceal – which makes the overall project look nicer.

One of the best reasons to use a wiring kit is the wires are labeled and mapping out the wiring harness is that much easier because each wire is identified to the component the wire routes to. Grounds are important and unlike fuses, too many grounds don’t cause a problem. Most wiring experts will choose a spot on or near the firewall for the common ground point for the harness, and one point for a chassis ground on the negative side of the vehicle. This method gives you a single path to the negative side of the vehicle and provides a more effective ground. Use 10 gauge or bigger wire to connect the common ground to your chassis ground.

Bowers points out that a steel frame is a poor conductor of ground current since it only conducts 12- to 16-percent that copper does. He suggests grounding the negative cable directly to the engine block or transmission case. “Keep the ground cable close to the starter for the least resistance,” said Bowers. “Ground the frame and the body to the engine block or transmission case to be safe.”

There are two types of connectors offered in automotive wiring; soldered and solderless. Most automotive pros do not like to use soldered connections. Solder tends to wick up in the copper wire above the connection, making a length of the wire solid. Solid wire is not used in automotive wiring because it is not flexible enough and won’t stand up to the vibrations created during driving.

Use solderless connections wherever possible. These connection are typically the butt connectors that splice two wires together. Cylindrical shaped, wire is inserted into each end and crimped to make the connection complete. Splices are a last resort and should only be used when replacing the wire with the correct length is not an option.

Spade connectors are typically used when components are removed for service frequently. A complete spade connection consists of a male connector and a female connector that join to make a complete connection. The two connectors simply pull apart to disconnect.

Ring connectors are generally used to connect wires to screw-type terminals. They are connected to the terminal by a terminal screw. These can be used in circuits that are frequently disconnected.

Bowers says that it is a great idea to use shrink tubing on the connections. It is easy to install and use, and provides great protection against the elements. “Cable ties, grommets, clamps, boots, under-carpet wire channels, and zip looms also come in handy when routing wires through firewalls and under the interior. “Take your time, stay organized, and installing a wire kit can be the most rewarding part of a project car upgrade.”

For more information on wiring kits and pro-tips to automotive wiring, visit the folks at Ron Francis Wiring online at

1.25mm Pin Header Suppliers for Sale

Build your own custom newsletter with the content you love from FordMuscle, directly to your inbox, absolutely FREE!

We promise not to use your email address for anything but exclusive updates from the Power Automedia Network.

2 Wire Male Female Connector, Twisted Wire Harness, Vehicle Wire Harness - SYM,