Horn problems

[Tom _M]

Have an '07 MkII Focus that has a non-working horn. Checked the fuse and relay, and those both seemed okay. Took the old horn off, and using some wire/crocodile clips tried it on the battery to test it. It made a static type noise, but no beep. So presumed that was the problem. Ordered a used replacement off eBay, but when all hooked up, still no beep...

I tried that wired direct again, and made a similar crackly noise. I'm working on the assumption that it should actually beep when I do this right? I have a multimeter (though not really sure what am doing) and using continuity testing, it did show a current running though the horn.

So have I been unlucky and ended up with another duff horn, or am I missing something? My other thought of what can go wrong is the clock spring, but I'd like to know it is actually this and not the horn itself before I start faffing about with that.

Ta.

[GreenV8S]

Connect it straight to the battery with an inline fuse. If that doesn't work, check the battery is fully charged. Make sure you're connecting the earth as well as 12V side i.e. don't rely on mounting brackets etc to provide a good enough earth for testing.

If / when you have proved it works, then it should be straight forward to trace through the circuit with a volt meter to find out where your voltage is getting lost.

[imagineifyeswill]

Why are you messing about with secondhand horns a new one from motor factors would only be about £7.

[MC Bodge]

As above, connect straight to the battery, using larger diameter cable, with a relay triggered by the original horn wiring (check that is is providing ~12V). Dual (or triple) tone horns sound much better than a single tone. Air horns are even better.

[finlo]

If your clock spring has snapped you would also have an airbag warning light on.

[PositronicRay]

finlo said:

If your clock spring has snapped you would also have an airbag warning light on.

Sometimes you get just one wire fractured within the assembly.

[E-bmw]

finlo said:

If your clock spring has snapped you would also have an airbag warning light on.

He also tested it by connecting directly to the battery, so that doesn't use the clock spring.

[E-bmw]

You have likely bought a duff one, it could also be that the earth isn't good as above, or that it is quite simply seized internally. Get a new one, they aren't much.

https://www.ebay.co.uk/itm/1-Pair-Universal-139DB-...

[MC Bodge]

One of the dual tone aftermarket horns I fitted to one of my motorbikes stopped working, resulting in a feeble mono tone.

When I removed the snail shell cover, I discovered that a small piece of grit had becone lodged in the horn preventing the cone moving.

[Tom _M]

Thanks all, though I fear some may be over-estimating my technical ability a touch...

I got a used one as the electrical clip connector is the same fitting, whereas on a generic type one they're not, and it seems a bit much faff trying to put new fittings on.

Am I right in thinking if I put the two probes of the voltmeter into the two holes on the horn connector in the car and press the horn button, then I should get a voltage reading?

[Tom _M]

I should also add that when I press the horn button, I can't hear any clicking or anything to suggest the relay has current going to it. Would that noise be obvious?