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New 12v Horn Won't Sound

Old 08-15-2018, 08:02 AM
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At 3.5 amps if the helm is going from 14v to 12v you have a short somewhere.
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Old 08-18-2018, 05:08 PM
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Originally Posted by underpsi68 View Post
At 3.5 amps if the helm is going from 14v to 12v you have a short somewhere.
Fun times.

Can the switch be bad and causing that drop?

Keith
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Old 08-18-2018, 10:27 PM
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I agree, is the switch good, do you have power to the switch. a 12 Volt automotive horn has little to no draw, I doubt it the wire gauge, but worth a try I guess.
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Old 08-21-2018, 09:25 AM
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Tested the Contura 2 switch and it's good. There's only 2 wires going to it, power in and power out to the horn. I unplugged them from the switch and touched together. I get the same result from the horn. Next up is running a horn power wire from the helm to the horn and touching to the helm supply power to it and seeing what it nets. If it doesn't sound, it's gotta be the ground which will be tons of fun.

Keith
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Old 08-21-2018, 09:42 AM
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Sounds like the new horn has a greater current draw, you should use a relay and pull power from your amp wiring or similar, even if you get it to work with bigger wiring the switch probably wont last
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Old 08-21-2018, 10:48 AM
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The draw is 3.5 Amps as posted above. The switch is rated at 20 amps. Where are power to switches typically pulled from in the helm? That would require modifying source to the battery?

Keith

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Old 08-21-2018, 11:27 AM
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Typically the helm power comes directly from a distribution block that is fed from the batteries. On many boats the gauge of that wire is barely enough to get the job done with the stock components blowers etc.. If you have a one wire alternator then you will not see the designed voltage at the dash. Marine alternators have remote voltage sensing in order to compensate for the distance. Assuming it is as designed you should first try supplying a temporary new ground direct from the battery or ground block, then try running power from the battery or distribution panel, a "power probe" is a great tool to have for problems like yours.

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Old 08-21-2018, 11:54 AM
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Originally Posted by Wobble View Post
Typically the helm power comes directly from a distribution block that is fed from the batteries. On many boats the gauge of that wire is barely enough to get the job done with the stock components blowers etc.. If you have a one wire alternator then you will not see the designed voltage at the dash. Marine alternators have remote voltage sensing in order to compensate for the distance. Assuming it is as designed you should first try supplying a temporary new ground direct from the battery or ground block, then try running power from the battery or distribution panel, a "power probe" is a great tool to have for problems like yours.

Its not a 1 wire alt. its a circa 1996 Mando on 7.4l LX MPIs. Also even at engine running volts (13.8-14 typically), still no sound and the battery gauge crashes 2v upon sounding the horn.


A power probe as in test light or are speaking of something else?

Thanks for the above info. Off to find the power & distribution blocks. Im guessing somewhere near the breaker panel.
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Old 08-21-2018, 12:15 PM
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Originally Posted by Tractionless View Post



Its not a 1 wire alt. its a circa 1996 Mando on 7.4l LX MPIs. Also even at engine running volts (13.8-14 typically), still no sound and the battery gauge crashes 2v upon sounding the horn.


A power probe as in test light or are speaking of something else?

Thanks for the above info. Off to find the power & distribution blocks. Im guessing somewhere near the breaker panel.
power probe 3 or 4 is capable of not only being a test light, but also supplying a ground and or +12v/24v to anything 12 or 24vdc that you may be working on. Most useful electrical tool I own and rarely stays put up for long, with the optional extension you can diagnose trailer lights in no time for example
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Old 08-25-2018, 12:28 PM
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Picked up a Power Probe after some research. In the meantime I ran the 10ga power wire from helm to horn today which did not fix the issue.
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