2006 Montauk 170 Horn, Navigation Lights

Electrical and electronic topics for small boats
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Joined: Wed Apr 27, 2016 10:32 pm

2006 Montauk 170 Horn, Navigation Lights

Postby moabelite » Wed Apr 27, 2016 10:40 pm

I put my 2006 Montauk 170r to bed last fall with no known [problems]. On the season opening run earlier this month the horn would not work. Upon investigation I found:

--the navigation lights are also not working reliably but will occasionally turn on without clear indication of cause for failure, that is, I can't wiggle a wire and get the lights on;

--the compass lamp also gets power on the same circuit as the navigation lighting switch, and it illuminates every time the switch is toggled. This leads me to rule out power to the switch and the switch itself;

--the horn is not working at all.

My hypothesis is that the horn has a defect that is the cause. Or, that a harness is lose.

Any thoughts?

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Location: Michigan, Lower Peninsula

Re: 2006 Montauk 170 Horn, Navigation Lights

Postby jimh » Thu Apr 28, 2016 12:52 am

I don't understand the relationship between the HORN, the NAV LIGHTS, and the COMPASS LIGHT. Are they all controlled by the same switch? I would think not.

To diagnose the horn's failure to work, measured the voltage at the horn on the circuit supplying power to the horn. If 12-Volts is supplied to the HORN when you push the horn button, and the horn does not sound, then the likely cause is a defect in the horn. If there is no voltage at the horn, you have to discover the cause of the discontinuity in the circuit.

To diagnose the problem with the navigation lighting circuit, you must again measure the voltage supplied to the lamps. I believe there are at least two lamps in this circuit, a combined sidelights lamp and a white all-round lamp. We can use these lamps as indicators of voltage in the circuit. If both lamps simultaneously illuminate or extinguish, then the problem is most likely in a circuit element that is common to both lamps. That would generally be at the switch controlling these lamps. If only one of the lamps illuminates or extinguishes, the problem is isolated to that portion of the circuit, to the lamp fixture, or to the lightbulb in the fixture.

Read this article in the REFERENCE Section:

http://continuouswave.com/whaler/refere ... Start.html

The article describes many methods and techniques for finding problems in simple electrical control circuits. In particular, perform the procedure described under the sub-heading Electrical Diagnostic Technique. This will help you locate the point in the circuit where electrical power distribution is being interrupted.

Posts: 21
Joined: Wed Apr 27, 2016 10:32 pm

Re: 2006 Montauk 170 Horn, Navigation Lights

Postby moabelite » Sat Apr 30, 2016 10:28 pm

Thanks for the detailed and helpful reply Jim!

I made if back to the boat today to investigate further and of course found the horn to be in working order today! Nothing worse than a problem that comes and goes. I was unable to get the horn to fail today and will have to monitor accordingly.

I did, however, diagnose the malfunction with the navigation lights. In fact, upon looking on the old forum tonight, I see that a similar problem has been discussed here:


So, I'm off to order a new lens and will have to do my best to ensure the tabs don't break.