OMC System Check check

[guy48065]

The previous owner of my pontoon chopped the main harness when replacing the carpet. The boat has no gauges so I suppose he figured "no loss".
Well I want to add the System Check warning horn & lights to my boat so I bought a replacement harness. It came with the horn. I expected the horn to sound when I started the motor (like it says in the manual) but it didn't make a peep. So I'm wondering if the horn doesn't work unless you ALSO have the System Check gauge with the warning lights?

The OB is a 2000 Johnson 2C 40HP (J40PLSSM)

 

[dingbat]

My system check tachometer cycles through a series of beeps and lights every time I turn the key.

I'm guessing the relay logic for the alarms resides within the system check unit.

 

[guy48065]

I would have thought the logic resides in the outboard but maybe you're right. I've ordered the gauge.

 

[dingbat]

I would have thought the logic resides in the outboard but maybe you're right. I've ordered the gauge.

Without the system check all the sensors are wired in parallel. The new harness breaks them out into individual circuits for interpretation by the system check.