How to Wire a Universal Ignition Switch

by Jack Hathcoat
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wire cutters image by Jim Mills from

Universal ignition switches are used on off-road vehicles, boats, generators and industrial equipment. They are durable and easy to install, but they offer very little in the way of security. Wiring is straightforward, with threaded studs on the back of the switch over which eyelet connectors fit, and the eyelets are held in place by tightening small nuts. A high-quality design switch will last for decades, and because of their broad application, these switches are likely to be in use well into the future.

Step 1

Draw a wiring schematic. This is critical for a successful job. The back of the switch is marked with the function of the switch. The switch positions are "Acc" for accessory, "R" for run, "S" for start and "Off" for off. Plan each circuit carefully and include circuit protection, either inline fuses or a fuse panel, in the diagram.

Step 2

Cut wires to the length needed that run from the ignition switch location to the circuit protection. The accessories part of the ignition powers the accessories part of the fuse panel, such as radio, park lights and hazard flashers. The run wire powers the entire fuse panel. The start wire only supplies two circuits: the starter solenoid and the ignition.

Step 3

Strip 1/4 inch off the insulation on the wire and crimp connectors to the bare copper. Use different color wires, and select wires that are heavy enough to power the circuits. The run wire should be 10-gauge, the accessories wire 12-gauge, and the start wire 14-gauge.

Step 4

Install the wire on the ignition switch and tighten the retaining screws with a wrench. Route the wires to the fuse box location and install the wires on the box. Different fuse panels have different attachment methods. Universal fuse panels often have studs that secure the wires with attachment nuts. Tighten the wires in place with a wrench.

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