Q about Mercury alert horn

[TraceF3]

I recently got a small bay boat with a Merc 150 EFI. There is no engine alert horn when the ignition is turned on. I cannot find one under the dash.

I have installed a Merc Smartcraft monitor, it has a pigtail in the blue CAN cable behind the gauge, 2 wires for a horn. I bought a new one and connected it. Still no horn.

I tested the new horn by putting 12v to it directly to it and it works.

Where on the original harness should the connectors be for the horn? And by connecting the blue CAN cable for the Smartcraft monitor have I disabled it?

Thanks in advance...

[JOE54]

should see purple and tan blue strp coming off key harness , what ser number for engine id , next forum down has more info for your engine if its 2 strk

[TraceF3]

2006 Merc 150 EFI

1B379725

[TraceF3]

Should I have a horn connected to both the harness and the blue CAN cable?

[TraceF3]

I am able to get about 4' of the cables out of the floor. The ignition switch has 6 wires connecting to a 6 wire connector. From there down it's covered with a black shield into the floor. There is another similar bunch of shielded wires coming up and splitting out to the kill switch, shift control box, etc. Neither has any pigtails sticking out within 4' of the console end.

[EuropeanAM]

Should I have a horn connected to both the harness and the blue CAN cable?

NO. There should be a warning horn on the KEYSWITCH HARNESS. The wiring on any external Can-P cable is for an optional LOW DEPTH warning (required an optional depth transducer).

Your warning horn should be attached to the keyswitch harness, within 3' of the key switch in most cases.

[TraceF3]

I am able to get about 4' of the cables out of the floor. The ignition switch has 6 wires connecting to a 6 wire connector. From there down it's covered with a black shield into the floor. There is another similar bunch of shielded wires coming up and splitting out to the kill switch, shift control box, etc. Neither has any pigtails sticking out within 4' of the console end.

Additionally, when I reset fuel used on the Merc monitor the horn gave me a 1-second chirp.

[EuropeanAM]

Do you hear one test tone when you turn the key to "ON"?

The warning horn wires are a purple wire, and a tank w/blue-stripe wire.

[TraceF3]

No sir I have no key on sound. Or any other sounds for that matter. I ran the boat this weekend and I have at least 3 hours over 4,000 rpm's. Still have the 2 icons flashing. I have a VVM coming hoping it will tell me more.

[SilverFox579]

FWIW that's a Smartcraft System Monitor and the chirp you heard when resetting fuel used came from it not the warning horn Don is referring to. Really do need the warning horn.

[TraceF3]

FWIW that's a Smartcraft System Monitor and the chirp you heard when resetting fuel used came from it not the warning horn Don is referring to. Really do need the warning horn.

I get it. But as I said, I can't find the pigtails. I can only get about 4' of the harness out of the floor before I run out of slack to pull. IF I could find the pigtails I'd have to make up extensions or the horn would be under the floor.

[fastfiat]

I just replaced the warning horn on my boat. Thought it would be a plug and play situation but after pulling all the electrical tape from the end of the old horn wires I found out it had been soldered directly to the appropriate wires coming from the switch. There were no pigtails from my ignition switch. Switch was probably replaced at one time and the aftermarket switch had no pigtails to plug the switch into. Looking at switches on line it looks like some have pigtails for the horn and some don't.

[TraceF3]

I think the pigtails would come from the motor where the faults occur, not the switch. The only way I'm getting to them (if they exist) is by taking the harness loose from the motor, pulling enough of it into the console and splicing extensions on to it, then pulling the harness back to reconnect to the motor.

[SilverFox579]

Warning horn pigtails should be in the harness that comes off the key switch. Reason the horn is at the key switch vs motor is to ensure you hear it when an alarm occurs.

[TraceF3]

Warning horn pigtails should be in the harness that comes off the key switch. Reason the horn is at the key switch vs motor is to ensure you hear it when an alarm occurs.

I understand this. What I meant is the signal that sounds the horn is coming from the engine. I have always found them (pigtails) within 2 or 3 feet of the switch but the wires are coming from the engine I believe. This harness doesn't have them where they usually are.

[JOE54]

likely not a genuine OEM harness then

[EuropeanAM]

Are there any places where you can see the wire colors IN that harness? If so... look for the tank w/blue stripe. It terminates AT the warning horn, and at the engine.

[TraceF3]

I pulled the boot covering all the wiring going from the console into the floor to get my hand in the cavity. The harness has a plug with a cap that says 120 ohm. It's below the floor and hard to get to. Aside from that I can't find any pigtails. That's what I am looking for correct? A male and female single wire pigtail? I'm 4 1/2 feet from the switch at that point.

Is it possible to splice the wires at the motor and run them up to the console to connect a horn?

[EuropeanAM]

If it's got a 120 ohm (blue) resistor it's almost certainly a Mercury harness.

I would not tinker with running wires from the engine. They ARE up there at the console somewhere. Just being overlooked, or hidden, or ???

It should be MUCH closer to the switch... and it's not much larger in diameter than a quarter.

[TraceF3]

Here's what I have. About 4 inches below the floor is where the 120 ohm plug and terminator is.

I can get my hand in the hole and pull the cap off but I can't get it above the floor.



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