Horn not working

The horn on my 2012 isn't working. I've swapped the 10A fuse and the relay in the engine compartment fuse box but no change. Cruise control works so I'm not sure if the clock spring is the issue. When I press the panic button on the keyfob the horn will honk.

What should I check next?

 

It's likely the spiral cable. The proper way to diagnose it is to remove the steering column cover and ground the horn wire to ensure the circuit to the spiral cable is good.

 

Thanks @Bishop84. I'll give it a shot. Do you happen to know what color wire I should be hunting for in the steering column? I assumed since the CC was working that wasn't the issue but it's probably because I was hoping it was just the relay.

 

The horns require a ground through the body of the horn mounting assembly. You can unplug and see if you're getting a +12V at the horn connector. If you are, likely you just need to clean up the ground connection on the body. These days, they paint the body first then put the connectors on so alot of 'ground' connectors that go to the body don't get a great connection unfortunately. Modern car designers don't understand simple flow of electrons, but they make them look nice.

 

Here's the schematic for the horn circuit you'll note it's positive switched by the horn relay with the body of the horn assembly providing return current.

 

My money is on the spiral cable:

 

Me too. Spiral Cable.

OP just unplug the Green with Red Stripe wire in the steering wheel and ground it. If the horn blows then the spiral cable is the problem.

 

I agree, that's probably the most likely culprit.

 

Also check the wires leading to the horn. I had one wire snap off from the connector, and the other one was a bit loose.

 

Horn works when I hit the panic button on the keyfob. I'm thinking that rules out a connection issue at the horn.

I'm going to check the clock spring/spiral cable later today.

 

So there isn't a green with red stripe that I'm seeing. *edit: the green with red stripe is in the terminal on the other end of the clock spring, not right behind the steering wheel*

The blue wire appears to be the ground from the horn. Should I ground that to test the wiring? *edit: that is the ground for the horn switch*


It connects to the horn switch/airbag at this terminal by the screwdriver


When grounding the wire that plugs into the horn switch I get nothing. I'll run back out and test the green/red wire at the terminal later today but everything is pointing to the clock spring so far.

Here's a video that helped me troubleshoot.

 

That is the Green with Red Stripe I was talking about. It's in the video that you attached.

See the print that was posted above and in your video you linked Green with Red Stripe behind the steering wheel.

 

Yeah. That's what I figured out once I got further into it. Horn honked when I grounded the green/red but did nothing when grounding the blue wire that connects to the horn switch. Going to pick up a new spiral cable tomorrow.

 

Exactly! Spiral Cable is bad.

 

$20 SeaSense Air Horn – Jumbo Size (8 oz), 127 dB – Loud 1 Mile Range, Meets EPA & USCG Standards – Great for Boat & Marine Safety, Ideal for Sporting Events Such as Football & Soccer

https://www.amazon.com/SeaSense-50074080-AIR-Horn-Large/dp/B078MJZV49

Just in case the spiral cable doesn't fix it...

As an aside, I was looking for a diagram for this, thinking about some aftermarket horns. o.x Stock horn is kinda weak.

 

Fuse

 

I have notes/pics on the pins for the horn through the spiral cable in my notes about the cruise control here:
https://www.tacomaworld.com/threads/couple-notes-on-cruise-control-install.730008/#post-26000184

 

It was the clock spring/spiral cable. Installed a new one and the horn is working again.

If you read all the first post you'll see I had already ruled out the fuse and relay.