How to Wire a Boat Ignition Switch

Written by Shaina Bakshi
on Jan 04, 2011

To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.

Reviewed by
H.R. Helm
on Nov 15, 2019

Drill

Spray vinyl electrical insulation

Hole saw

Rosin core solder

Soldering iron

Drill

Spray vinyl electrical insulation

Hole saw

Rosin core solder

Soldering iron

Your boat ignition switch requires replacement when the switch does not provide electricity to the engine without efforts. Wiring the regular three-post ignition switch for the outboard may be a difficult task to some boaters who do not know the technical details of the boat wiring. It is indeed an easy process to wire a boat's ignition switch. Usually, all ignition switches have the same basic function despite its additional features, i.e., the basic circuit is the same for all the ignition switches. These ignition switches are basically used to control the power going to the primary side of the starter solenoid and the shipboard. When the switch is in the on mode the circuit is completed. These ignition switches are used in boats, off road vehicles, industrial equipment and generators.

These switches are easy to install and durable. Even though these ignition switches are not used widely due to lack of knowledge about them. It has 6 terminals on its back, with two of them marked with the same letter, a boat's ignition switch wiring appears to be a challenging task. But it can easily performed by following the steps given below.

Step 1: Drilling

First, use a hole saw tool to drill a 1-1/2 inch hole in the dash at the location where the ignition switch has to be mounted.

Step 2: Sliding Down the Bezel

Then once the hole is drilled, slide down the ignition switch into the bezel which will be provided with the switch. Then, thread the plastic nut onto the underside of the switch and tighten it such that it holds the bezel in place.

Step 3: Soldering “B” Terminal

Next, pull up the ignition cable through the hole in the dash. The terminal on the switch which is marked as "B" has to be located. Then find the red wire in the ignition cable with a purple stripe throughout its length. Using soldering iron, solder it to the "B" terminal along with the rosin core solder.

Step 4: Soldering “A” Terminal

After soldering the “B” terminal, it is time to solder the “A” terminal. Solder the purple wire into the "A" terminal. Next , solder the purple wire with a white stripe along its length to the "C" terminal. Then, solder the yellow wire with a red stripe on it to the "S" terminal.

Step 5: Spraying

After soldering the terminals specified in the previous steps, solder the black wire with a yellow stripe to any one of the two terminals which is marked as "M". Then, solder the black wire with a white stripe to the another terminal which is marked as "M". Finally, using the spray vinyl electrical insulation, spray all the terminal connections. Now, mount the ignition switch in the dash with the mounting screws that are already provided. You have successfully wired your boat's ignition switch.

Tips And Warnings

If you leave the ignition switch of your boat turned on, the starting battery will deplete. Use a house battery along with the starting battery and change the battery selector switch to the house battery and turn off the ignition switch.
The wiring information about the boat is available in the boat owners manual that specifies details about the ignition switch.