How to Wire a Boat's Ignition Switch

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If your boat's ignition switch no longer lights the fires of your engine without effort--perhaps you have to wiggle the key in the switch, or you may even have to wiggle a loose ignition switch in the dash--the time for replacement has arrived. With six terminals on its back, two of them marked with the same letter, a boat's ignition switch appears to present a challenge, but it's a challenge in appearance only.

Items you will need

  • Drill

  • Hole saw

  • Soldering iron

  • Silver core solder

  • Spray vinyl electrical insulation

Use a hole saw to drill a 1-1/2 inch hole in your dash where you want to mount the ignition switch.

Slip the ignition switch into the bezel provided with the switch. Thread the plastic nut onto the back of the switch and tighten it to hold the bezel in place.

Pull the ignition cable through the hole in the dash. Find the terminal on the switch that's marked "B." Locate the wire in the ignition cable that's red with a purple stripe along its length. Solder it to the "B" terminal with silver core solder and a soldering iron.

Solder the purple wire to the "A" terminal. Solder the wire that's purple with a white stripe to the "C" terminal. Solder the wire that's yellow with a red stripe to the "S" terminal.

Solder the black wire with a yellow stripe to either of the two terminals marked "M." Solder the black wire with a white stripe to the other terminal marked "M." Spray all the terminal connections with spray vinyl electrical insulation. Mount the ignition switch in the dash with the supplied mounting screws.