Re: Boat Switch Diagram
Don't start replacing things unless you know they are bad. That's a poor, and expensive way to troubleshoot. The gauges are all interconnected and power to them is from the "A" (accessory) terminal on the ignition switch. Use a test light or voltmeter to see if you have power on the "A" terminal when the key is on. If there is, the ignition switch is not the problem. If there is no power on the "A" terminal, check the "B" terminal. This terminal gets power from the battery via the engine electrical harness. But if that terminal has no power on it the engine wouldn't crank. Follow the wire to the first gauge in the string and measure again. Keep following the voltage until you lose it. If you have +12 volts at the "I" terminal on all of the gauges, then there is probably a bad ground. Use the ohm meter to verify this. If the meter shows open circuit you found the problem.
