Horn not working on 2001 Maxum 2300sc

[SimonM]

Here's a puzzle for you all... my horn on my Maxum 2300sc has stopped working... I removed the horn from the bow and tested it across the 12v battery and it sounds just fine... I then put my multi-meter across the yellow and brown/green wires feeding the horn and they send 12v when the horn button is depressed at the helm... so, there is nothing wrong with the horn itself and the wires deliver 12v when the button is pressed, but when it's all connected together, the horn does not sound when the button is depressed...

Any ideas?

[mmwjr]

Well if 12 V is present on the wires at the horn and the horn works if you directly apply power I can only assume the contacts need to be cleaned on the horn and wires.

You are measuring power on the wires directly where they connect to the horn, correct? There is a relay between the button and horn.

[Phillbo]

Turn on your docking lights

[mmwjr]

One more test. Try measuring for 12 V with the horn connected. If the horn relay has pitted contacts it could cause a voltage drop that is not present in the open circuit test you did.

[shrew]

Are you getting 12v on the wires, or 12v-ish? The electric horns are cranky about low voltage.

[SimonM]

Thanks for all the replies...
- I am getting 12+V at the wires
- I have cleaned the terminals to within an inch of their lives
- when (if) it stops raining, I'll try testing with the horn connected

Very frustrating, as you can imagine... I'll keep you updated...

[SimonM]

OK... it stopped raining, so here's what I did (it's STILL not working, btw):
- I removed the horn completely and sanded the terminals to within an inch of their lives... shiny shiny copper now
- I tested the horn on my car battery and it woke Australia, so no problem there
- I cut off the female spade connectors and replaced with new, so the connections at the business end of the horn should be fine now
- I removed the push switch and emery papered the terminals there, too... and squirted a liberal amount of WD40 everywhere just for good measure
- I tested the push-button switch with the continuity setting on my multi-meter and that works fine

Unless I'm missing something, perhaps Shrew is right and I'm only getting 11.5V (or less?) at the terminals (enough to move the needle on my multi-meter, but not enough to sound the horn)... so, I've put battery 1 on charge overnight and will try in the morning...

Unless anyone else has any better ideas, I'll let you know what happens in the morning... I'm still open to suggestions...

Cheers,
Simon

[mmwjr]

As I said if the relay has pitted contacts a voltage drop will occur 11.5v or less is the result. Get a digital meter and get more accurate readings.

[SimonM]

Thanks Mike... it MUST be that, as I have had the battery on charge all night and no joy this morning

Do you know where I shoudl start hunting for said relay?... behind the dash, or somewhere else?

Thanks,
Simon

[oneradride]

Ground.... Ground.... Ground.... boats are wood and fiber glass.... You have 12V and you apparently have a "negative source" somewhere because it sounds as if you are testing the circuit. Run a jumper wire from the (-) on the horn to your negative test light source or a (-) on the battery and see what happens

[SimonM]

Thanks Darren... would you know off hand if the Yellow is ground or the Blue & Green?

[oneradride]

Sorry I don't know off hand but there should only be 2 posts on the horn. It's the one not getting the 12V

[mmwjr]

Yellow is the negative. Horn relay should be under the helm, start at the horn switch and trace the wire until you find it.

[jamanati]

Disconnect the horn, connect a 12v test light inline those wires. does it light brilliantly or dimmly?
If its bright, something is up your horn.
If its dimm, disconnect the ground from the test light. Connect it to a "good", perhaps straight to the battery.
Is it still dimm? If it is, you have a bad/low/power/hot wire.
If its bright, you have a bad ground back to your switch.

[mmwjr]

Originally Posted by jamanati

Disconnect the horn, connect a 12v test light inline those wires. does it light brilliantly or dimmly?
If its bright, something is up your horn.
If its dimm, disconnect the ground from the test light. Connect it to a "good", perhaps straight to the battery.
Is it still dimm? If it is, you have a bad/low/power/hot wire.
If its bright, you have a bad ground back to your switch.

Good test procedure but I prefer to use a DVM (digital volt meter) and get real reading. Hard to tell a bright 10 V light from a 12V one.

[SimonM]

Thanks again, all, I will get a DVM, find the relay and clean and run a wire from the "yellow" terminal back to the battery and test again...

Cheers,
Simon

[SimonM]

Curious... it just started working again all on its own ... I guess it was a voltage issue after all?

[mmwjr]

Originally Posted by SimonM

Curious... it just started working again all on its own ... I guess it was a voltage issue after all?

Probably either a poor connection or bad contacts in the horn switch or relay

[Adrian]

Hi Simon, how did you go, I have the same problem with my horn, I have replaced the switch and cleaned the wires still no joy

[mmwjr]

Adrian see post #15 of this thread on how to proceed.