Installing Automatic Car Interior Lights: Wiring

What You'll Need
Car Interior Lights
Open-end Wrench
Toggle Switch
Wire Cutters
Soldering Iron
Heat Shrink
12V Fuse

In the search of improving the interior look of the car, many people choose to install car interior lights. This is not a difficult process as long as you pay special attention to the wiring. Here is how to wire the car interior lights properly.

Step 1 – Examine and Mount the Car Interior Lights

Examine the set you’ve bought from the automobile parts store to see what is included. The lights will be already wired with a short length of wire. Some sets have switches and fuses included. If your set doesn’t have these parts, buy them separately. Buy some additional wires too just to ensure that the wire length will be sufficient for your car. Then choose a suitable place for your car’s interior lights and mount them

Step 2 – Disconnect the Battery

Since you will be doing a lot of wiring, you should in all cases disconnect the car battery. This will help you avoid unpleasant accidents during the installation process. The disconnection is done by removing the negative cable from the battery, using an open-end wrench. Make sure that the cable isn’t touching the chassis or any other metal part of the car.

Step 3 – Measure the Wires

Measure the length of the wires. They must be long enough to directly reach the car battery via your car’s existing firewall holes. If needed, add some more wire length by soldering additional wires to the original ones and then applying heat shrink over the solder connections.

Step 4 – Mount the Toggle Switch

The 2-way toggle switch should be connected at a part of the positive wire that allows you to mount the switch on the driver dashboard. Take the wire cutters and cut the positive wire in 2 at the suitable point. Then connect the switch to the wire by joining the wire’s 2 free ends to it. Finally, mount the switch on the dashboard.

Step 5 – Run the Positive and Negative Wires to the Battery

To run the wires to the battery, use the existing holes of your car’s firewall. These holes are located underneath the car dashboard and all wires coming into the car compartment pass through them.

Step 6 – Mount the Fuse

You have to mount a fuse to the positive wire, in order to increase the reliability of the electrical chain. Cut the wire in 2 and then solder the fuse to the ends. The fuse must be no further than 50cm from the battery. Apply heat shrink to the solder connections if needed.

Step 7 – Connect the Positive and Negative Wires

Connect the positive and negative wires directly to the car battery. In theory the negative wire can be wired to any bare metal part of the chassis, but in real life this is unsafe.

Step 8 – Inspect your Work

Reconnect the battery, turn the power on and see if the lights are working properly. If they are weak or shimmering, you may have done bad wiring at some point.