Horn Stopped Working

My horn stopped working about 2 months ago in my 2010 Prius. I stopped O'Reilly ' s Auto and the guy showed me where the fuse was but it 2 as good. If it needed to be replaced he said it has to come from Toyota because it is a Jumbo fuse that has three in one. So the problem is either in the horn itself located in front of the radiator or in the steering wheel where the airbag is at. My horn works when the alarm goes off so I am guessing it is in the steering wheel. Am wondering if the air bag recall has anything to do with it but they say my car is not one of them. :$(

 

I'm facing similar issue and trying to troubleshoot. Did the other buttons on your steering wheel work? For me, it's just the horn that doesn't work when pressed.

 

Very interested in this thread, just realized my horn hasn’t been working.

 

me too. my horn works, but you never know

 

If you hold the horn pad in the pressed position and turn the wheel around to different positions, does the horn beep in some places and not others?

If so, that's a smoking gun for the spiral cable behind the wheel.

If not, then you haven't found a smoking gun; could still be the spiral cable, or be something else.

 

OK, I've done some investigating with the horn. My PANIC button on my fob kicks on the horn- so I know the horn itself isn't the problem. I've tried honking the horn with the wheel turned in various positions, both for left and right turns, minor and major turns, but that doesn't seem to be it either. I did, after driving around for a while and constantly trying to honk my horn by pushing on it at various locations on the face of the airbag, find ONE spot that if I press on it, sounds the horn. It's an area that's in the left, bottom section of the airbag area and I can reliably get it to honk if, and only if, I press it in this one location on the pad.

So, what does this indicate? Is it this "spiral cable" or do I have some kind of dirt/dust/debris that's causing the other switches that must exist between the pad and the wheel, that are in need of cleaning or replacing?

 

Exactly the kind of thing I'd look for. If I remember right, the horn contacts are open and exposed behind there. A set of them might be kind of oxidized or dirty, or there might even be something in the way back there, like a wire that happened to fold the wrong way when the pad was last installed.

Should be pretty simple to find, but will mean taking the airbag out. Be sure to bone up on all the safety rules for that.

 

I found this excellent video on YouTube.

 

It's not bad. For your own purposes, you're not likely to need any more of it than the part for getting the airbag off.

The 12 volt battery is disconnected as soon as either terminal is. No need to do both. No need to fuss with the orange traction battery plug at all. You're not going to be doing any high-voltage system work here. A quicker way to disconnect the 12 volt battery is just to unplug the fat white cable in the underhood fuse box. (In my car, that would leave some of my added toys still powered that are connected right back at the battery. But it depowers all the stuff that came with the car, which is what matters here.)

The more willing you are to work on those plastic cover panels without metal picks and such, the fewer unsightly gouges and scratches they'll have when you're done.

Once he has the airbag out, he puts it out of the way in the back seat, off camera. That makes this a good place for an open-book safety quiz: whenever you set down an airbag, you set it down which way up?

Once you've done that, you should have no problem seeing what's up with the horn contacts. The horn beeps when that blue wire attached to the airbag gets grounded (to the metal frame of the steering wheel itself, mounted solidly on the steering shaft). The structure that the airbag pops into is normally insulated from the grounded parts, except when you are pushing on it, and you should be able to find the contacts that touch when you do that.



Only for future readers who would want to follow that video further, say to replace the spiral cable:

Mating marks are good for the wheel and the steering shaft. A mating mark on the nut won't necessarily tell you when it's properly retightened; a torque wrench is better. Toyota does not specify Loctite for the nut, as long as it's correctly torqued.

Avoid pulling a lock pin from a new spiral cable before the spiral cable is installed on the properly-centered steering shaft with the wheels straight ahead. If you're transferring over the steering angle sensor from an old cable like the guy in the video, and you have his problem with the sensor tabs not lining up with the spiral cable notches, don't forget the sensor also can be turned. (You don't run into that problem if you buy a Toyota spiral cable, which comes with the sensor already.)

 

my car beeps when turn the wheel while in pressed position.
smoking gun issue? do I need to replace this part or spiral cable whole part?

Thanks

 

If the car beeps, intermittently, as you turn the wheel, while holding the horn pad steadily pressed, then yes, that is a smoking gun for the spiral cable.