No alarm on startup

[Rebbasser]

Howdy y'all!<br />I've got a 2001 Mercury 115 on a Nitro 750 NX, and the low oil/overheat alarm does not sound when I turn the key. At the same time, there is a horn under the console that has a button on the dash. It also has stopped working. There is power going to the button but none going to the horn. Looking for suggestions.<br />Thanks!

 

[ronmold]

Re: No alarm on startup

did the horn work w/o the key on?

 

[Rebbasser]

Re: No alarm on startup

Nope. Makes me think there is a short in there somewhere-the horn as well as the alarms on startup were working and just stopped.

 

[ronmold]

Re: No alarm on startup

The "Horn w/ button on dash" - is that a warning horn for other boats, like a car horn or an engine warning horn?

 

[Rebbasser]

Re: No alarm on startup

As a warning for other boats. Can't hear it above the outboard, but it is there. It's completely useless if you ask me, but like I said: It stopped working, and the alarms that are supposed to sound when you turn the key stopped working as well, which leads me to think they are related.

 

[ronmold]

Re: No alarm on startup

You lost the +12v (purple) that feeds the buzzer & horn circuit. could be a fuse. Is the motor carbureted or EFI? Carb engines just use the ground (black) and switchbox kill (black & yellow) wires to enable the ignition. You must be getting +12v to the switch because you can engage the starter. The oil warning buzzer gets +12v when the key is on and the buzzer sounds off when the - lead (tan/blue) is grounded at the oil warning module or the high temp sender goes off. use a 12v test light or meter to make sure the purple terminal is hot w/ the key on

 

[Rebbasser]

Re: No alarm on startup

Motor is carburated, and I checked the juice on the purple lead from the ignition and it is hot. The only fuses I could find is a fuse box under the console and none are blown. Am I missing an in-line fuse somewhere?

 

[ronmold]

Re: No alarm on startup

Keep tracing the purple all the way to the warning buzzer. If you have juice there ground the tan/blu wire on the engine going to the warning box. If the key is on the buzzer should go off. As for the horn do the same. The + will either go to the switch and the horn is grounded (most common) or the horn is wired hot and they run the (-) to the switch that is grounded. A 12v test light w/ a sharp probe end is better than a meter because it actually puts a real load on the circuit being tested. A meter can read right through a corroded terminal showing 12v because there is so little current required to get the meter to go.

 

[Rebbasser]

Re: No alarm on startup

Am using the 12V test light and will keep you posted. Thanks for your help!