Weak horn

[Ron Lime]

This is a weird problem that I'm wondering if anyone else has dealt with....

1986 Sundancer 268DA. Horn was not working so I replaced it with a similar model from West Marine. It worked after install.

A few weeks down the line and it sounds like a sick duck. Can barely hear it. My Blue Sea SOC indicates it's drawing ~ 15 amps but no useful noise.

I started troubleshooting it by running a temporary + line directly from the battery and splicing it in. I worked backwards from the horn and now have proven that if I connect my temporary + wire to the 'in' side of the horn fuse holder the horn works!

The switch panel receives a + buss from the battery switch to the first fuse holder (cockpit lights) and then there is a 3 inch jumper from each fuse holder to the next, down to the horn (last fuse).

If I jumper from the first to the last fuse, still no useful noise.

My cockpit lights, nav lights, water pump, bilge pump, blower all work fine off this buss.

So that + buss is good enough for EVERYTHING except the horn.

Before I run a new dedicated + wire for the horn fuse, I thought I'd see if the collective had any other ideas to try.

Thanks.

 

[Stee6043]

Generally it's water in the horns that make them sound like sick ducks. Do you have the horn location that fires upward-ish from the hullside? These are the most prone to collecting water. I've read around here of folks that drill a hole (somewhere?) to help with drainage.

 

[Ron Lime]

Horn is fine. If I hot-wire directly to the battery it works. And the horn is 3 weeks new.

 

[Stee6043]

Horn is fine. If I hot-wire directly to the battery it works. And the horn is 3 weeks new.

Copy. I saw sick duck and skipped the rest. Ha. Good luck!

 

[Ron Lime]

Problem solved. Apparently the new horn needs a little higher voltage to start than the old horn.

After lots of isolation testing of each segment, I determined that the total loss on the circuit was too much. So I ran new 10ga wire from the horn (connection in the head compartment) to the push button. (Was 14 ga) That removed enough loss and now the horn sounds!

 

[RBB]

I have had spiders gob up the horn. Cleaned it out works great.

 

[SCORPIO]

Make sure both power and ground are clean and tight. I had similar issue, turned out to be a bad ground, butt splice was only holding about 3 strands if wire. Replaced and horn is normal.

 

[Carpediem44DB]

Problem solved. Apparently the new horn needs a little higher voltage to start than the old horn.

After lots of isolation testing of each segment, I determined that the total loss on the circuit was too much. So I ran new 10ga wire from the horn (connection in the head compartment) to the push button. (Was 14 ga) That removed enough loss and now the horn sounds!

I've had similar issues on boats I've owned over the years and always turned out to be the wiring was too small of gauge. The horns take a bit more amperage than lights but the manufactures commonly run too light of wire. The horn works for a while but then suffers due to increased resistance.
Carpe Diem