Car Restoration – Replacing Car Wiring



To restore car electrical assembly is an important step that should not be missed. All your mechanical components are linked together by wires. And if you are performing a car restoration you must never overlook the importance of wiring. 30, 40 or older wiring is more often than not very corroded and even tough you may rebuild the motor and install lots of shiny new parts, wiring is what ensures that it all works properly, and allows you to keep track of it all. Here, the guys at Jeff Lillys restoration show you how what you will need to replace and how to go about it.

This is a basic wiring kit from Painless. It includes the fuse block as well as some of the essential wiring.

/

Depending on the new features you may be adding to your hot rod, you may want to consider a powerful alternator. This Power Master alternator puts out 190 amps. This should be enough to power a good stereo, A/C, fuel injection and a bunch of other stuff.

/

Every component will require a specific amount of electrical current and a different fuse. It’s important to be able to have access as well as making sure to have it in a safe spot. Be sure to keep your wiring away from heat sources like this fuel injection box.

/

To start off, find a safe and proper spot for your fuse block. In this case it will be in the trunk, behind the side panel. Here it will be accessible yet out of sight.

/

Here, the fuse box is screwed into place with stainless steel screws and the wiring is passed over the wheelhouse.

/

This wiring will run through the rocker panel, a hole is cut out for it to fit through.

/

It is good to sand down all the areas where wires may touch metal so that  the surface is smooth and will not cut the wires.
/

Also you should limit the wires movements in the openings that they pass through.

/

Always use corrugated conduit to protect the wires from chafing directly on metal. You can use a string to pull the wiring through long openings like this rocker panel.

/

This main junction block will go under the dash to feed to different electrical components.

/

You can see the feeds coming off to their perspective areas. Don’t forget to shrink wrap any soldered connections.

/

Sometimes you will have to hide parts like this starter solenoid

/

Here some of the preliminary wires are run up the dash. Note the markings above the knobs, this allows you to easily keep track of what goes where.

/

This project is fuel injected with a medium rise tunnel air intake. This makes room for some hidden wires for the 8 injectors and other wires in the front of the motor. Once in place they will have to wrapped in shrink tubing.

/

You can buy battery cables in bulk at your local parts store.

/

Once the knob control components have been wired in, the wires will be trimmed to correct length.

/

Use clamps and zipties to keep the wires in place.

/

Here is the wire harness for all the dash knobs. Once all the components are wired in and tested you can wrap the harness in electrical tape.

/

Some kits come with small labels naming all wire components. You could always add your own if they do not.

/

Often you will need to replace the entire switch, then you will have to reassemble it in order to maintain the original knob.

/
/
/
/

The brain of the fuel injection unit is mounted in a safe place under the dash, away from most heat sources and allowing for easy access if needed.

/

The fuel injection unit comes with it’s own fuses and electrical relays.

/

Most older style steering columns are not equipped with emergency flasher systems. This simple isolator with diodes will incorporate the emergency flasher system to the new wiring.

/

Little brackets such as this u channel are very handy when holding up wiring.
/

In this case there will be two separate batteries, one being used solely for the stereo.

/

The 1 gauge battery cable runs over the trunk panel to the second battery in this custom Ford.

/

These European snap plugs are another handy wiring component and are completely waterproof.

/

You should carefully cut away pressed in tail light pigtails as they are often too corroded to be reused.

/

The tail light housing may need to be filed to fit new sockets.

/

/

Replace and rewire the headlight connectors as well and do not forget to shrink wrap to keep out moisture.

/

It is best to cross the headlight harness under the radiator support, but can also be installed on top.

/

These headlight and other front end wires are run under the driver side front fender, note the special cover to protect them from tire debris.

/

When dealing with fuel injection, remember to run the wires for the O2 sensors in the headers, these will have to be welded in to the headers.

/

Don’t forget to power everything up to ensure that it is all working properly. Do not wait until the car is running to do this, as it is best to make any changes while it is all still fresh and easily accessible.

/

And that it about it. Of course this example includes a lot of custom additions and replacements. When simply rewiring a car to original manufactured standards, it should be much easier as you have the originals in place and can just follow along with them.