Horn works using electric power and, just like any other electrics-dependant part, it has a fuse. If the fuse is blown, you’ll simply need to replace it. Modern car fuses have that fork-like look and if the wire between them is broken, then you’ve found your problem.

Locate the horn or horns on the radiator core support or behind the car’s grille. Remove the wire connector. The horn should resemble a fuse with wires coming out of it.

Car horns sit up front where they’re exposed to rain and road chemicals. But an inoperative horn can also be caused by a bad horn switch in your steering wheel, a broken “clock spring” under the steering wheel, a bum horn relay, a broken wire or a corroded ground.

The two main reasons a car horn won’t stop honking include a failure in the switch and a failure in the relay. Failing that, if you are unable to immediately locate the correct fuse or relay, pulling the main fuse or disconnecting the battery will also allow you to address the problem without damaging your hearing.

If a battery has no trouble starting an engine, it should have no trouble sounding a horn (with the engine off). Once the engine is running, the battery only comes into play when the vehicle’s electrical demands are too much for the alternator to handle. The horn takes power from car battery only.

Now, how long you leave a car without starting will totally depend on the condition of your car’s battery. Most modern cars with a somewhat healthy battery should be able to last at least 2 weeks.

Ways to Revive a Dead Car Battery

1. Jumpstart: Jumper cables and a second battery, battery booster, or second vehicle might be enough to jumpstart the vehicle.
2. Distilled Water: If the electrolyte level is low, adding distilled water might be enough to fully-submerge the plates and enable a bit more reaction area.