How to Hook Up a Toggle Switch in a Car
- 1). Drill a 1/2-inch hole and mount the toggle switch. Tighten the retainer ring with a wrench. Test the existing wiring with a test light to determine a suitable power source. Turn the ignition key on and off, and isolate key-on or key-off power. Install a fuse tap in the fuse box if the toggle switch is illuminated.
- 2). Cut the wiring to the lengths needed to power an illuminated switch, running from the fuse box to the toggle switch. Strip 1/4-inch of the wiring insulation from each end of the wire and crimp terminal connectors onto the bare copper. Plug one connector onto the fuse tap and another onto the center pole of the illuminated switch.
- 3). Cut a wire to length that runs from the battery to the toggle switch and another from the toggle switch to the component that the switch controls. Install terminal ends on the wires. The illuminated toggle switch can only be used to control the ground (negative) circuit. Plug in the wire coming from the negative battery terminal onto one of the outer terminals of the toggle switch. Plug the remaining wire onto the remaining outer terminal and route it to the negative lead of the component being controlled.
- 4). Wire the two prongs of the non-illuminated toggle switch in either a negative control or positive control configuration. Use the positive wire from the fuse tap to connect to one of the two leads. Run another wire from the toggle switch to the positive lead of the component being controlled. Wire a negative control circuit in a similar fashion, except reverse the polarity -- make ground or negative connections instead of voltage supply connections. Either process is acceptable.
