Horn Problems

[venomx]

2008 MK2 Yaris.

Looking at the MOT history the Horn was not working back in 2018, and when I got it MOT last month, it failed on the horn ( and then was fixed so it'd pass the MOT )

I did get the front offside arm pin/bush replaced a couple of weeks after the MOT

 

I tried the horn today, not working. I tried the fuse, and it looked intact, tried a spare one, still no luck.

When I press the horn I hear a slight clicking noise but no horn noise.

I'll get the mechanic on it asap. But why would it keep going faulty even though I rarely use it ( if at all )

[Mooly]

It might need nothing more than adjustment... horns are very crude things actually. If you look at the horn there should be an adjustment screw. Give it a turn either way while you keep trying the horn.

 

 

[venomx]

3 minutes ago, Mooly said:

It might need nothing more than adjustment... horns are very crude things actually. If you look at the horn there should be an adjustment screw. Give it a turn either way while you keep trying the horn.

 

 

OK thanks. Can this be done without removing the front bumper?

[Bernard Foy]

Also check out the earth where its fixed to the car 

[Mooly]

9 minutes ago, venomx said:

Can this be done without removing the front bumper?

I have no idea on the Yaris but would be surprised if it was that complicated. Perhaps just unbolt the horn for better access.  

[corradovr6]

On the mk1 its easily accessible with no bonnet removal. If it is the same on yours there will be only one ,(positive) spade connector with the ground (negative) through the mounting bolt. If you can connect a meter to the two connectors while someone presses the horn you'll identify where the problem is. Prob just easiest to buy an equivalent replacement.  They're only about £7 or 8 on eBay

[venomx]

18 minutes ago, Mooly said:

I have no idea on the Yaris but would be surprised if it was that complicated. Perhaps just unbolt the horn for better access.  

When I had it " fixed " a month ago at the MOT centre, he told me it would involve removing the front bumper to fix it

[Mooly]

1 hour ago, corradovr6 said:

 If you can connect a meter to the two connectors while someone presses the horn you'll identify where the problem is........

A meter would probably show 12 volts (normal). The problem are the contacts (contacts as in the 'make and break' contacts on the armature or diaphragm) that need adjusting. Its a common issue generally, it even happened to me on an Audi years ago. 

1 hour ago, venomx said:

When I had it " fixed " a month ago at the MOT centre, he told me it would involve removing the front bumper to fix it

Without seeing one for real I can't say but I would be really really surprised if Toyota made that it difficult. Have you actually looked and located the horn?  

[Cyker]

IIRC it's mounted on the front crash bar, so I suspect you'd need to remove the bumper to get at it.

To be fair, the front bumper of the Mk2 is fairly easy to remove - It's mostly held in by plastic push-pins, a few 10mm bolts and some guide/alignment posts, and weighs nothing

I don't think the horn is a common failure point; I'd put my money on a dodgy wire or connector somewhere, or possibly the relay.

If you feel adventurous and have a 12v source like a spare car Battery, you can try powering the horn directly to see if it works before getting more invasive!.

[wildtapholer]

When our Yaris went in for the air bag recall, the horn wouldn't work when we got home, but hey who would check that, it was only because they had the air bag off I knew it was their doing, took it back, they didn't say what they did but it worked after and still denied it was their doing but didn't charge.

[flash22]

16 hours ago, wildtapholer said:

When our Yaris went in for the air bag recall, the horn wouldn't work when we got home, but hey who would check that, it was only because they had the air bag off I knew it was their doing, took it back, they didn't say what they did but it worked after and still denied it was their doing but didn't charge.

They plugged in the single wire, for the horn (spade attaches to the airbag)

 

Back to the op's post, With the car running hold the horn and turn it lock to lock a few times if it sounds and any point it's likely the clock spring aka spiral cable - a burnt out relay maybe another cause

[Cyker]

That's a good shout - Came across a few posts and a youtube video where a dodgy clockspring cable in the steering wheel was responsible for horn failure, although in other cars, not a Yaris!

 

[flash22]

The horn is usually the first thing to fail as it's usually one of the outermost tracks, if left you end up with no audio controls or an airbag light

the cable typically cracks just where it mounts to the backplate, it's only a thin flat flex

 

[Cyker]

I can imagine... those things are the bane of my life when I'm trying to upgrade or repair a laptop... (That and structural things like hinges being screwed into plastic - I'm looking at you HP!!)

 

[flash22]

Laptop repair was one of my specialities some in store brands like packard bell and e-machines are a mare to work on the bigger stores have their own SKU's and custom specced machines that you will not find anywhere else - the Sony Vios were utter rubbish, you were locked in and had to use their proprietary hardware, and it was also locked to the bios with a very small whitelist of upgrades

 

car audio wise - Nissan connect systems are built to a price, look at the PCB the wrong way and the tracks just vaporize - ford radios are a bit clunky - GM are a nightmare for being coded to everything, want to change a display or add sat nav - coded and/or locked out

[venomx]

Got it fixed. Mechanic said it was something to do with the "earth" wire

[Mooly]

Well that's good although I'm a little puzzled what must have been done (post #1) to fix the horn originally so it passed its MOT.

Hopefully all good for you now.

 

[stantheman1]

^....Probably a long screwdriver or similar to shift the horn on its mount thereby temporarily scraping any surface rust or debris away, for a permanent fix remove the mounting bolt and clean both areas that create the ground/negative point. Or it could be the clock spring that's been 'wiped' a few times.