Maximus Mercedes Benz Horn

Maximus Universal Twin Snail Horn - Mercedes Benz Sound, 12V

Maximus sells these as a set of two 12V snail horns, one high-pitched and one low, tuned to give the deep two-tone sound you hear from a Mercedes-Benz. This is a universal horn. It is not built for Mercedes cars, and it fits any 12V car, SUV or pickup with room to mount it, from an Alto to a Hilux. The horns are made in China. Most people who buy a set have a factory horn that has gone weak or croaky, or they are tired of the thin single beep their Mehran, Alto or Cultus came with.

Each unit works the way every electric horn has worked for about a century. Inside is a copper coil and a thin steel diaphragm. Power the coil and it drags the diaphragm inward, which breaks a contact and cuts the current, so a spring pushes the diaphragm back out and the contact closes again. At 400 to 500 times a second you hear that as a note. The snail shell around it is a trumpet coiled up to save space. Sound has to travel round the spiral before it gets out, and that longer path moves a lot more air, which is why an 80mm snail horn is so much louder than a flat disc horn of the same size.

Why it comes as a pair - high tone and low tone

Look at the bracket on each horn and you will find H or L stamped next to the frequency. The H unit sits around 500 Hz and the L around 400 Hz, and both are wired to fire at the same moment. With roughly 100 Hz between them the two notes clash slightly, and the ear hears that clash as louder and more urgent than one note would be. European carmakers have fitted horns in pairs for decades for this reason.

The caveat that only shows up after you have fitted a few of these: mount the horns with the sound outlet pointing downward or horizontally, never facing up. The manufacturer builds them to IP65, which means rain and a pressure-washer jet will not get into the driver. IP65 says nothing about water sitting still. The spiral is an open funnel, and fitted face-up behind the grille it fills during the first proper Lahore monsoon, the water rests against the diaphragm, and within a few weeks the horn goes hoarse. Most "the horn died in three months" complaints are a mounting angle problem, not a manufacturing one.

What it cannot do and where it does not fit

• It is not a pressure or air horn. At 105-118 dB it is a loud electric horn, in the same class as the horn on a new Civic or Sportage. If you are expecting bus or truck volume, you need a compressor-fed air horn kit, and those carry their own legal problems on city roads.
• It is not a Mercedes-specific part. "Mercedes Benz" in the name refers to the sound. There is no Mercedes part number and no vehicle-specific plug, so it installs the same way on a Mercedes as on any other car. Anyone restoring a W124 or W140 who needs the original factory horn should buy the genuine part.
• It is 12V only. Do not fit it to a 24V truck, tractor or bus system. The coil will not survive it.
• Space is the real fitment question, not the vehicle. Each horn body is 80mm across, 91mm tall and 83mm deep front to back, before you add the bracket. On Mehran, Alto and older Cultus the area behind the grille is shallow and already carries the radiator support and washer bottle. Measure the gap first. Many cars take both units without trouble; some take one behind the grille and one down by the bumper beam. If your front end has less than about 90mm of depth, a flat disc horn is the better buy.
• They are not light. At 0.66 kg a unit, they need a proper steel mounting point. A plastic clip or a bent sheet-metal tab from a lighter horn will fatigue and crack.

How to fit it

1. Take the negative lead off the battery first. On most cars sold here that is a single 10mm nut.
2. Find the original horn. On most Japanese and Korean cars it sits behind the front bumper on the driver's side, on a small L-shaped bracket bolted to the slam panel or the bumper reinforcement.
3. Unbolt the old horn. Each new horn has its own 1.2mm steel bracket with an 8.5mm mounting hole, which takes a standard M8 bolt.
4. Mount each unit with the opening facing down or forward and down. Bolt them to steel, not to a plastic bumper skin or a radiator shroud.
5. There are two spade terminals on the back of each horn. One takes the positive feed and the other takes an earth wire. The bracket is not an earth path on these, so run that second wire to bare metal on the chassis. Bolt it onto paint or underseal and the horn stays quiet.
6. Wire the pair through a relay. Take the relay's power feed straight from the battery positive through a fuse, and use the car's original horn wire only as the trigger. Most factory horn circuits on small Pakistani-market cars were designed for one small horn, and the switch contacts inside the steering wheel are thin.
7. Reconnect the battery and test. If only one horn sounds, check that unit's earth wire first.

The mistake people actually make is skipping the relay because "the old horn worked without one." Each of these draws up to 4A, so the pair pulls close to 8A together. Run that through the steering-wheel horn button and the contacts pit, the clock spring heats up, and months later the airbag warning light comes on because the same slip ring carries both circuits. The relay costs very little and it protects a part that is expensive to replace.

The second mistake is bolting both horns to one bracket so they touch each other or the bumper skin. The casing has to be free to shake. Let it lean on plastic trim or on the other horn and part of that movement goes into the trim instead of the air, so the set sounds flatter than it should.

Specifications

Who buys this

The largest group is owners of Mehran, Alto, WagonR, Cultus, City and Corolla whose original horn has faded to a weak squawk after eight or ten years of humidity and road grime. A horn is one of the few parts where the factory item on an economy car is genuinely undersized, and replacing it is a thirty-minute job with a spanner.

The second group drives long distances on GT Road and the motorway network, where the useful function of a horn is warning a truck driver who is drifting across a lane line at night. A single weak disc does not reach him through a closed cab. A two-tone pair does.

Ride-hailing and delivery drivers buy these because they use the horn fifty times a day and the factory unit wears out fast. Workshop owners buy them in twos and threes for the same reason.

If you want the loudest possible sound and you are not worried about subtlety, look at an air horn kit with a compressor instead. If your car has less than 90mm behind the grille, buy a slim disc horn. If you need the exact Mercedes original for a restoration, this is not that part and our parts counter can source the genuine number instead.

Where to buy

The Maximus Mercedes Benz Horn is stocked at Sehgal Motors branches in Lahore, Faisalabad, Sialkot and Multan, and on sehgalmotors.pk with delivery across Pakistan. Stock moves quickly on horns, so if you want to collect the same day, call ahead on 0311-1222357 and the branch will hold a set. Our counter staff can also tell you, by car model, whether both units will sit behind the grille or whether one needs to go on the bumper beam.