Getting ready to rewire your classic car? Here are five tips from Capp’s Hot Rods and American Autowire to get you on your way:

1. Identify your project.
This is not an easy task because it really does depend on the car you are starting with. If your project is a typical street rod, then you have a far more complex task at hand. This almost always requires a complete rebuild and a conversion to a 12 volt electrical system. If you are starting with a running car, you may not need to replace all of the harnesses in the car. However, this can change with a complete restoration. Remember, there are many options to handle your project and there is not a “one size fits all” solution.

2. Plan your project.
The most important part of the project involves your “wish list” of electrical system accessories that you want in or on the car. Once you have determined those accessories, you can determine how many circuits or how many amps you need to feed those accessories.

3. Research what’s available.
You have identified your project, and you’ve decided the extent of modifications and the mix of accessories you want. The next step is to find out what’s available. There are basically two major categories of harness products: original replacement and generic rewire products.
a. Original replacement harnesses, such as American Autowire’s Factory Fit® product line, are available for most factory cars from 1955 and up. This is by far the easiest way to rewire, since the harnesses are plug in replacements made specifically for the vehicle in question. Some vehicle attributes must be defined in more detail because there were many factory options available for each model.  Although these harnesses generally cost more, installation time is much shorter and requires less skill. The most common alterations for alternators and ignition systems are also available as complete plug in modifications. Keep in mind that a minimum of additional circuits will be available for “wish list” items.
b. Generic rewire kits require more work on the part of the installer. However, there is a wide area of kits that range from vehicle-specific update kits, such as American Autowire’s Classic Update Series, to totally generic and universal wiring kits, such as American Autowire’s Power Plus, Builder, and Highway Series kits. These require the most research on the part of the customer. The time spent really knowing the alternatives, the concept behind the kit, inclusions with the kit, and the reputation of the manufacturer is time well spent.

4. Determine your comfort level.
You will have to assess your level of expertise and your capability to install the wiring system based on your research. Aside from the daunting task of rewiring, you have to decide if the kit description satisfies your level of expertise. The level of documentation that exists, experiences of friends, magazine installation articles, and direct contact with the manufacturer’s customer service department will all help make this determination.

5. Select the wiring system best suited to your requirements and the car.
If your project is a totally custom street rod, a more generic kit such as the Highway Series, Builder series, or Power Plus series kit is in order. The decision here centers on the number of power circuits required and the type of kit design. A general rule concerning the number of circuits is that if your wish list contains items that you think you may want to install later, it’s wise to purchase a kit with more circuit capability now. This will allow easier installation later as the power handling capability will already be in place. The second part of this decision centers on the selection of a modular or integrated fuse box kit. Modular kits are represented in the Highway series 15 and 22 kits. These are easier to install because none of the wires are pre-connected to the fuse panel and all of the power circuits are wired from the outside into the fuse panel (i.e. you place the fuse box and then wire everything into it). Panel placement is not constrained and circuits that are not used are not connected. This prevents live circuits that will have to be capped off before the system goes live. Integrated fuse panel kits are represented by the Power Plus and Builder Series kits. These fuse panels are designed to mount under the dash. All connections are done from the fuse box out requiring termination of each wire at the final connection point. These systems are less flexible in the panel mounting location so they may present more routing issues than a modular system. The Classic Update Series kits combine aspects of a generic kit, with those of a vehicle-specific kit. Classic Update kits provide as much plug and play capability as possible, while accommodating the increased circuitry and free routing requirements of a street rod kit design. These kits are designed around a specific group of vehicles. Original switches, heater controls, tail lights, parking lights, factory gauges, and dash design are incorporated into the design of these kits. If this kit exists for your vehicle, it will be the most complete option available to you, saving considerable time and effort in the rewire project.

Finally, if a truly plug and play system is required or the need exists to restore your vehicle to original specifications, the Factory Fit® line of harnesses will be your solution. Modification harnesses exist to address charging system and ignition system updates. While the cost of these harnesses is more than the generic kits, considerably less time is spent in installation.

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With over 40 years of combined restoration experience, Capp’s Hot Rods rebuilds and restores Model As, Deuces, ’33s and up, classic cars of all makes and models, and muscle cars.  Located in Woodland Hills, California, Capp’s specializes in complete wiring services, from repairs to complete harness installations.  Visit their website or call 818-974-7530 for more information, or to schedule an appointment for your classic car.  You can also find the Capp’s team at the Pomona Swap Meet on Road 22, Spaces 22, 24 and 26.