How to repair a dead horn?

[greenhorn]

My Hella Redgrilles had stopped working, and the car electrical shops all recommended replacing them. Now having paid 1.5k for them, and with the box having "repairable" on it, I'd kept them with me, and finally got around to opening them. Now there is a lot of black material covering the contacts. and one of them doesnt have continuity between the horn contacts unless I press them hard. My initial thought was to get some fine grade emery (400 grit?) and clean them, but then I thought of contact cleaner sprays, but I don't think they would be enough.

Emery paper should be fine , right? or am I doing something wrong?

[anujmishra]

These are carbon deposits and I think fine-grit emery paper will do the job. Additionally you have to adjust the various gaps inside horns. Once it is done pack neatly, ensure all nuts and bolts are present and then do the tuning by connecting directly to battery terminal (with some ear-plugs).

[sgiitk]

By and large my experience with horns is that repairs do not even last three months, so better replace them. Cars with twin horns you may try repairs but definitely do not try on single horns jobs.

[akshay4587]

I have used Red Grills for quite sometime,and i still remember that the amount i spent on their repairs was more than their actual cost.Every time the electrician used to replace a small metal strip inside.

[Warwithwheels]

The STOCK horns in my Figo go dead quite often. When I press the horn pad whenever the horn goes dead all that I hear is a click click sound from the area near the bonnet release lever.

After repeated tries, it springs back to life. Any guess what could be the culprit?

BTW... I reported this to the Ford service personnel and he (over the phone) suggested that my horn would need to be tuned. What does this "horn tuning" mean? I always thought only Guitars and Violins can be tuned

[greenhorn]

there is a screw behind the horn that adjusts the gap between the horn contacts. Im guessing it modifies the frequency also. I tried running the horn with a 2A adapter, and it was a hit and miss affair. Will test it once the car comes back next week. Will also say if the screw actually modifies the frequency

Originally Posted by akshay4587

I have used Red Grills for quite sometime,and i still remember that the amount i spent on their repairs was more than their actual cost.Every time the electrician used to replace a small metal strip inside.

Can the strips be changed? it looks like they're riveted to me

[Aroy]

Repairing horns is as easy as cleaning the contacts with fine sand paper, and blowing all the deposits inside the body. The contact and the plate can be changed by electricians.

For tuning use the screw at the back. Adjust the screw a bit at a time and press the horn.

[msaudf]

Originally Posted by Warwithwheels

I reported this to the Ford service personnel and he (over the phone) suggested that my horn would need to be tuned. What does this "horn tuning" mean? I always thought only Guitars and Violins can be tuned

Horn tuning is very similar to tuning the guitar and violin. The vibration of the strings create sounds, loose for low pitch and tight for high pitch, so in case of a horn instead of adjusting the temper of the strings, the electrician adjusts the contact distance of the horn points to the horn plate.
I haven't opened up a horn but I imagine this is what happens inside the contraption.

[Aroy]

Apart from tuning using the rear screw, you can also alter the pitch by adjusting the tension of the diaphram (which has a nut in the centre). Be warned this is a very delicate adjustment and if you mess it up you will have a horn which changes its pitch with voltage

[BuildUpGypsy]

From my experience, it is clear that the horn sound is highly dependent on the mount. Performs well when the mount is rigid & non-vibrating. Especially those Megasonic kind of horns.

[jfxavier]

Originally Posted by BuildUpGypsy

From my experience, it is clear that the horn sound is highly dependent on the mount. Performs well when the mount is rigid & non-vibrating. Especially those Megasonic kind of horns.

Sometimes the mounting bracket or the place on the body where the horn is mounted is not rigid enough and the vibrations during operation of the horn can damage it. After repairs/ renewal please ensure that the horn is mounted properly. Otherwise the story might repeat itself. Some of the aftermarket "loud" horns can be a lot heavier than the original ones the car came with.

[gostel]

Pressure on contact can temporarily cure a bad internal contact. Clean the outside and try continuity without any pressure. If still dicey then check internal connection. The horn itself is a simple device. I use a INR 40/- buzzer for my home door bell. It is just the same thing, but for 12V operation.
Screw behind adjusts "travel" of magnetic strip inside. Less gap higher pitch of horn. Zero gap -> no vibration. Too large gap -> no pull -> no vibration.
Intermitent operation -> loose contact = check and solder joint.
No need to replace strip. If inside make/break contact is suspect then clean it with CTC (Carbon Tetra-chloride) liquid. Alternatively clean the contact with polish grade emery paper.

[zeri]

Saw this similar article on xbhp.com with pictures on how to repair horns.http://www.xbhp.com/talkies/do-yours...bile-horn.html

[Automaton]

Hi

Happened to be in Pune and my two tone horn went dead, the high tone. Didn't have time to go to the dealer as it would mean starting a job card and so on, just to replace a part, plus the labour, all of which adds up.

The horns were going dead with some regularity, so I decided to try out the two-three repair shops at Shankerseth Road, before heading back to Mumbai.

I am sure there are similar repairers in all the cities.

So this guy had a smattering of horns of all makes, and car companies.
Suzuki, Skoda, etc

He opened up my sealed Roots horn with a screw driver and hammer, pried open the clamped edges with a pair of pliers, and dropped the bits and pieces in a dark, oily liquid.

Then he cleaned the contacts, sprayed a bit of WD 40, then some oil all around and put it back together to tune the sound. Once he was satisfied, clamped the edges shut with the pliers.

Cost, Rs 100.

Dead horns according to him, are just dirt and carbon deposit, in need of some TLC.

[ketantendulkar]

Originally Posted by Automaton

So this guy had a smattering of horns of all makes, and car companies. He opened up my sealed Roots horn with a screw driver and hammer, pried open the clamped edges with a pair of pliers, and dropped the bits and pieces in a dark, oily liquid. Then he cleaned the contacts, sprayed a bit of WD 40, then some oil all around and put it back together to tune the sound. Once he was satisfied, clamped the edges shut with the pliers.

My Skoda Octavia's dual horn had reduced to a feeble single meek peep just a few weeks ago.

Thanks to @Automaton I was able to get it repaired at the shop mentioned below for Rs.200 (for two horns which he said were 'original' and of good quality - the brand said MICA or MICRA).

I visited Team-BHP after a blue moon and this was listed right at the top in the "hot threads" - god bless Team-BHP!!

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