To install a toggle switch in your car, you’ll need to drill a hole for the switch in your paneling and wire it in to the power supply. Make sure you disconnect all power from the device before you start to protect you from an electric shock. Then, remove all the paneling or housing around the device so you can access it. Drill a hole in the panel where you want your switch to go and push it through. You’ll need to measure the diameter of your switch so you know how big to make the hole. Once you’ve fitted your switch in the panel, cut the supply wire in your device. In the break, attach your toggle switch wires, using screws, solder, or twisting the ends, depending on your toggle switch. Finally, connect the power supply and test your switch. For more tips from our Electrician co-author, including how to buy the right toggle switch for your car, read on! here