Only when reasonably necessary to prevent a collision.
Never
You would need to check local legislation. Different countries and states have differing regulations concerning the use of a vehicle horn.
Blind pedestrians are around
The horn is located underneath the hood of the vehicle.
On a vehicle, the return path to the battery is through the vehicle's framework. The negative terminal of the battery is connected to the frame of the vehicle. The reason there is only one terminal on the horn is that, that is all that is needed to make the horn operate. Applying the positive side of the battery to the single terminal which is connected to the horn's coil will make it operate. When the horn is bolted to the vehicle this completes the circuit back to the negative terminal of the battery. Apply the 12VDC to the horn by pressing on the horn button which closes the circuit and the horn activates. A horn with only one terminal has its coil grounded internally within the horn. A horn with two terminals has the coil isolated from the ground. On a two terminal horn there needs to be a wire installed to the frame on one of the terminals to make the horn operate.
brakes
It is important to have a functioning horn in a vehicle for safety reasons. If everything else electrically is working for the horn, it is usually the clockspring that needs to be replaced.
YOU HAVE AN OPEN CIRCUIT THATS WHY THE HORN STAYS ON .(ITS A WIRE THAT IS MAKING GROUND.) DO YOU HEAR A CLICK WHEN YOU PRESS THE HORN BUTTON?
Requirement for a Horn on a VehicleThat depends on the law in the area where the vehicle is registered and/or operated.In most jurisdictions around the world, a horn is usually REQUIRED for safety, and usually a vehicle without a functioning horn will be denied inspection approval.
Most U.S. States Vehicle Codes only specify that a vehicle horn may not exceed the standard 110 decibels, or otherwise emit a harsh, or unreasonably loud sound. You may NOT equip, or otherwise replace your vehicles horn, with any siren, whistle, bell, or other type of audible warning device that is intended for emergency vehicle use only, if in fact your vehicle is NOT an emergency vehicle. (If you're a volunteer firefighter, check with your department for usage regulations.) I know of people who have substituted their vehicle horn for a boat horn-- that is, one that produces the same volume, but at a much higher pitch than a standard passenger car horn. Provided you don't abuse or "overuse" the horn, I doubt anyone in law enforcement will pay too much attention to your having it. For your State's Vehicle Code, which would outline the specifics for your own State, run a search in Google. Example: "Pennsylvania Motor Vehicle Inspection Code". Or call your local State Police Agency with questions.
The horn on a 1997 Hyundai is found mounted on the bumper of the vehicle. Remove the bolts that hold the horn down. Unplug the wiring and replace the horn.
Vehicles have a horn or a bell to alert people and let them know the vehicle is in the area. The horn is often used to prevent an accident.