2011 Prius Horn Not Working Diag Help Please

You could just pop off the steering column cover (can be done without removing the wheel even if the manual doesn't say so; just turn the wheel back and forth a bit for access to the two claws behind it) ... find the connector on the column side of the spiral cable (not the bright yellow one) ... unplug it and ground the horn wire (check wiring diagram for which pin/color that is) and see if the horn honks.

If it does honk when you ground that, then the spiral cable probably is the culprit (or just the horn contacts behind the airbag, but that'd be weird; you'd have to remove the airbag in either case anyway).

If that doesn't make it honk, then your spiral cable is probably ok, and you'll find the problem somewhere else (just follow the wiring diagram until you locate it).

-Chap

 

When you are done troubleshooting the horn circuit, there's a link in my signature below to a horn upgrade thread.

The FIAMM horns are plenty loud.

 

I see that Chap already answered the how-to. For horns, if I wanted loud, I'd get what I had on my motorcycle. Fiamm Freeway Blasters. One high and one low. 130 dB each at four feet. They each draw up to six amps, so I needed a bigger wire and a relay on the bike. I don't know the wire size on the Prius, but it might need something similar to get full volume.

Really fun to watch boneheads jump when they start to merge into your lane right next to you without looking. They have a nice automotive sound, too. Not shrill like an air horn or super low like a ship.

 

Before you do the intense diagnostic suggested by Chapman (which is fantastic, great idea!), I would try rotating your steering wheel in all directions and see if the horn works. On my 2nd gen my horn stopped working except when the steering wheel was 90 degrees to the left. Replacing the clock spring (which wasn't hard for me to do myself following YouTube tutorials with a $13 eBay replacement) solved my problem. If the horn only works with the steering wheel turned in particular positions it's almost certainly the clock spring.

 

Check your horn fuse and then follow Chapman's suggestion.

 

Whenever you're looking for the repair manuals, diagrams, and other technical literature for your car, techinfo.toyota.com is the URL you should know.

-Chap

 

Well, there's $pay and there's $$$PAY. I like to take a little perspective on the $15 ...

Last time I worked on my brakes, I got into a situation with an unfamiliar code I couldn't clear, ran out of time to fuss with it 'cause I was going out with people that night, and ended up driving them around with warning lights on my dash (and that is not a thing Chap does).

The following day I scraped up $15, looked up the answer, resolved the code, in and done. I even posted the answer on PriusChat at the end of a two year old thread where somebody else had the same exact code and never found the answer because nobody looked it up.

What's it worth to you to know exactly where the information is so you get your project done and move on to something else? (And, short of finding the exact answer you need on PriusChat, which is free and ideal when it happens, what would it cost you to solve the problem any other way?)

-Chap

 

If the error condition is cleared, you can try cycling the Prius On/Off several times and the error will clear. Usually takes about 5 to 10 times.

 

's funny ... the story of my life's been an ever-growing appreciation for engineering ... and the more I appreciate it, the more I find I look stuff up when I want to know it!

-Chap

 

Kevin,
This is what is happening with my horn! It works when rotated 90 degrees to the left, only. Toyota wants $800 for a new assembly, telling me it's a spiral cord. Now my radio is acting wonky. Is the Clock Spring different than the Spiral Cord? I have never taken off a steering wheel before but I'm all game, if I know I can't end up killing myself by destroying the air bag. Can you give me more detail on what the clock spring is and how to access it, PLEASE. Also, where and which part did you get to swap it out? Do I need to disconnect the 12V battery while doing this? I don't want to fry anything.
Thanks for any info you can supply!!!

 

It is not uncommon to disconnect the battery for doing any electrical work on a Prius and when you deal with an air bag you need to be extra careful and need the right step by step information that is in the repair manual like Chap mentioned above. Any work on the steering column this applies to.

 

Thanks Padroo. I have the manual from when I purchased the car in 2011, but I don't think I have a repair manual. Is this something I purchase from Toyota? Can you guide in the direction of where to get one? Thank you. edited: I see Chap's link to Toyota, I'll check there.

 

I see you already found the techinfo link.

For work around the airbags, yes, disconnecting the 12 volt battery is a must, not just for the usual reasons of protecting parts of the car from electrical mishaps, but for protecting parts of you from inadvertently deploying airbags.

The airbag system has its own backup power and can still deploy for up to a minute and a half after you unhook the battery. I generally just do that first, and by the time I've gathered the rest of my tools, etc., it's been plenty longer than that.

There aren't a lot of special tools needed, if you have basic sockets and a torque wrench, but the most civilized way to get the wheel off the steering shaft after removing the nut is with a steering wheel puller, which you may find a local auto parts store will let you borrow for a refundable deposit.

The manual will tell you this, but any time you set an airbag down, it should be bag up. The idea is, in the rare unlikely event of something like a static discharge setting it off, you just want the bag to pop out the top. You don't want the bag blowing out the bottom and launching the steel frame and inflator across the room at you.

-Chap

 

Clock spring and spiral cord are the same thing, correct. Basically it's the wiring that connects all steering wheel controls and the driver's airbag to the rest of the car's electronics. Your chance of firing the airbag unintentionally is essentially zero, so long as you disconnect the battery and wait two minutes before doing any electrical work.

There's not a specific tutorial for the Prius that I could find on YouTube, but there are many for Camrys and Corollas and it is exactly the same as these cars. Look on YouTube. Use these and a dose of common sense and the job isn't too hard. Need hex and socket wrenches. Hardest challenge is making sure to leave tape with lines so that when you reinstall the steering wheel, it is exactly straight.

This is what I bought: Amazon Link. (For 2nd gen Prius, if you have a 3rd gen likely need different part!) I originally used a cheap $13 one I bought off ebay, but it failed again after a little over a year, so I put the genuine Toyota one in.

 

Does anyone have recommendation for a spiral cable to fit a 2011 with GPS ? I don't want to spend $$ for Toyota product