Learn to Easily Install a Battery Disconnect Switch for Added Security

Installing a battery disconnect switch in a car can be a wise precaution for both racers and everyday drivers alike. This type of switch is wired to the car’s battery and can be used to cut off the power to the engine in emergency situations, making it particularly useful for race car drivers. It’s also helpful in anti-theft situations, so it can be a convenient tool for any driver. To install a battery disconnect switch correctly, use these step-by-step instructions.

The first step to installing a battery disconnect switch is to use a wrench to remove the connection on the battery’s negative terminal. Then, drill a hole through the car to the area where the switch is to be mounted. Depending on the specific use of the switch, different mounting locations may apply. Generally, it’s best to have it accessible from within the car; from there, you can pull back the carpet on the driver’s side and drill a hole into the engine compartment, preferably avoiding any obstacles on the other side, to route the wire up to the dashboard. Drill an additional hole in the dashboard if necessary to fit the switch through.

Next, cut a length of battery cable with a wire cutter that is sufficient to run through the car and up to the switch location. Make sure to leave an extra inch of insulation on each end of the wire before stripping it. Secure a terminal end on each of the stripped ends with a terminal crimper, then attach one of these terminal ends to the disconnect switch. Feed the opposite end of the wire through the hole that was drilled in the engine compartment and connect it to the other wire that is now connected to the switch.

Mount the switch in its chosen location, generally the dashboard, and then fasten the remaining terminal end to the negative post of the battery. Re-secure the negative terminal with the wrench. Finally, before concluding the installation, be sure to test the switch to make sure that it is functioning as intended.

All in all, installing a battery disconnect switch can be helpful in a variety of situations, from theft prevention to race car safety. Wiring it does require some coordination and knowledge of working with car batteries and electrical wiring, but by following the instructions step-by-step, the process should be relatively straightforward. Be sure to err on the side of caution, though—you want to be comfortable with the entire circuit before you declare it finished.