What is causing horn from steering wheel not to work?

If your 2007 Yaris horn emits quick beeps at random intervals while the car is running, it could be an indication of an underlying issue. Here are a few possibilities to consider:

1. Alarm System: Your Yaris may have an alarm system that is triggering the horn beeps. Check if the alarm system is armed and ensure it is functioning correctly. Review the alarm system's manual for instructions on how to adjust its settings or troubleshoot any issues.
2. Electrical Problem: The horn beeps could be caused by an electrical problem, such as a faulty horn switch or a short circuit. Inspect the wiring and connections associated with the horn and the steering wheel controls. Look for any loose or damaged wires, connectors, or switches. If you notice any issues, it may be necessary to have a professional mechanic diagnose and repair the electrical problem.
3. Malfunctioning Horn Relay: The horn relay is responsible for controlling the power supply to the horn. A malfunctioning relay can cause intermittent horn beeps. Consider checking and possibly replacing the horn relay if it is suspected to be the source of the problem.
4. Steering Wheel Controls: If the horn beeps occur when turning the steering wheel or when specific buttons or controls are pressed, there may be an issue with the steering wheel controls. Inspect the steering wheel for any visible damage or loose connections. If necessary, have a professional inspect and repair the steering wheel controls.

It is recommended to have a qualified mechanic or auto-electrician inspect your Yaris to diagnose the exact cause of the horn beeps. They can use diagnostic tools and their expertise to identify and resolve the issue more accurately.
Remember to consider your safety and the safety of others while driving. If the horn beeping becomes disruptive or potentially distracting, it may be best to temporarily disconnect the horn or seek professional assistance to avoid any hazards on the road.

there may be a problem with wiring in steering column? The horn switch on steering wheel and that wiring circuit is ground for control side of horn relay. The horn relay is not serviceable. If the relay was the problem, you could mount external relay. It just depends on the problem? If the horn sounds at all then I don't think the fuse is the problem. good luck

That means your horn and electrical to the horn are good. You may have a bad clock spring under the steering wheel, or a bad switch. Don't forget to check the horn fuse. It may have a different circuit than the FOB.

How to Fix Car Horn

Have someone listen under the hood for the sound of a clicking relay as someone actuates the horn ring. Remember if the horn does blow you might scare the listener!!!

If no click check for the under hood relay. If relay not activating check the horn ring. Some times adjacent relays have same pin out/part number. Swap relay and try. Many of the cars use a "clock spring" design on the wheel. Problem air bag circuit makes it difficult to service. Check to make sure all other services are working attached to the wheel (Speed control, radio,etc). If clock spring is failing eventually other circuits would be affected.

If you have key-less entry and have a horn beep confirmation try the FOB. No beep than maybe horn clock spring OK! In no horn beep confirmation try the panic on the FOB. That should make a little noise, and if nothing else you can check your lights.
Ck the fuse if OK
Hot wire horn if still no horn
Replace Horn

You have all the informations to find your problem. jump a wire on connector X4 G1 tan wire to ground and check X1 E5 with a test light or multimeter to see if there is a output, you should have 12 volts. If you dont have any voltage the horn relay is defective. I check in the shop manual and the relay come with the underhood fuse block.

it will be in the horn contact /ring/pin under the steering wheel. probably no contact to complete the circuit .

dead short at the horn button in the steering wheel

The HORN Is a GROUND CONTROLLED BUTTON you need to FIRST Check under CENTER STEERING WHEEL Cover to see if it has a Bad Commectiot, After Asuring this there Is c CLOCK Spring UNDER Steering Wheel that is Fairly Common for Failing.

The FOB / Remote Utilizes a Different Part of the Curcuit to Activate Horn, I Hope this Helps you With your Problem as Im Sure of All that I Advised. Remember to RATE ME !!

I've had this exact problem before when being jumped off. The fob DOES NOT make it stop. We removed the fuse that goes to the horn. As soon as your battery gets recharged from the alternator, the fob will work again and the alarm will quit sounding. The only pain about removing the fuse is that the cruise control will not work until you put it back.