have a 89 pro line cc with 225 mercury.... none of the gauges are working. The tach back light is on so it has power but does not register anything when reving motor. Fuel, temp, tach nothing registers anything....HELP!!!!!!!!!!
If none of the gauges work you need to turn on the key and make sure the first gauge in the string has +12 volts on the "I" (ignitiion) terminal. Which is the first gauge in the string? That would likely be the one closest to the ignition switch. If the first gauge has power, but doesn't work, then make sure it has a ground connection. Then repeat the tests for each gauge in the string. If you verify +12 volts and ground, at least the voltmeter should be working at this point. The other gauges won't show anything because the engine must be running. The fuel gauge should work without the engine running but the key on. While you may have a ground at the gauge, there may not be a ground connection back to the battery.
