First Post: Horn stuck on.

Hello, new member here, so please forgive me if this is not the right spot in the forum for this discussion. Thanks in advance for your help on the below.

I purchased a used 2000 tundra standard cab truck. So far really loving it, and looking forward to hauling a bunch of stuff in the super big bed. This is the V6 base model, everything is manual, no power locks, no power windows, etc.

In preparing for the safety check, i discovered the horn doesn't work. On further inspection, I then found that the two horn sirens, behind the grill, had be disconnected. Great, this should be easy to fix. But when i hooked them up, I discovered that the horn now was stuck on. Depressing the horn button in the middle of the steering wheel firmly -- did nothing. My neighbors were really loving my new truck by now...horn blaring for minutes.

I check the integration relay, and the wiring harness under the dash, the horn terminal has continuity to ground, regardless of the position of the horn button. So I don't think it is anything in the integration relay. I am suspecting it is the clockspring, but i can't really find much evidence online that supports a broken clockwheel leading to a horn stuck on condition. (Lots of examples of a broken clockspring leading to a non-functional horn, of course).

Furthermore the airbag dash light works as i would expect, and does go out a few seconds after the car starts. The clockspring controls no other functions, no radio, cruise control, etc. Only the horn and the airbag.

I did remove the airbag, hoping for some piece of something to be stuck in the actual horn mechanism. no such luck. even disconnecting the horn wire attached to the clockspring...and the horn is still on.

I didn't go any further, as i don't have the right puller to get the steering wheel off. But wanted to hear from you folks if anyone has seen anything like this with a stuck horn, before i go and replace the clockspring.

As I said, so far really liking the truck. Hauled a bunch of garden supplies this afternoon. It does needs a new exhaust system, i'm hoping that the manifold is OK. Also the wipers need work, i'm hoping that the motor does not need to be replaced, but it is awfully slow/weak.

Thanks all.

-k

 

At least they didn't hook up the horn relay to the brake lights. https://www.youtube.com/watch?v=vXYVa4VciK4

 

X2

Welcome from NY.

 

Unplug the horn and hook up a test light there instead while troubleshooting.

Your neighbors well appreciate it

 

Thanks for all the replies, very helpful!

So i replaced the clock spring. And unfortunately that did NOT solve the stuck horn problem. (Thanks for the test light tip, my neighbors do prefer that to the horn).

So now I am on to the integration relay replacement. I am a bit more nervous about this, as i don't see a lot of info online about this replacement, and what i do see has me replacing a circuit board inside that fuse box to the left of the steering column. So if you all have any further guidance i would appreciate it, otherwise i will carry on with the integration relay replacement...

Thank you as always,

-k

 

There should be a relay for the horn under the hood. Pull it and see if it shuts off.

 

Only other time I heard of a horn being stuck on. Probably not it if you don't have other symptoms though but here it is.
https://www.tundras.com/threads/help-horn-wont-stop-blowing.50621/#post-1320233

 

I would pull the wiring diagram. Look for a short to ground in the harness. Last car I had with a stuck horn was a wire damaged from a alarm system, cable had cut over time and was resting on metal. Aka stuck on

 

that video is hilarious!




Sorry I can't help OP. Wish I was off some help instead laughing at a video

 

I'll check this again. My previous research indicated that the relay for the horn, is part of the integration relay which is under the dashboard. There are actually test points at this integration relay, and testing these checkpoints also indicates that the horn is stuck on.

If indeed, from the below diagram, pin 12 has continuity to ground regardless of the position of the horn switch, does this suggest the the integration relay is OK, or the integration relay is NOT OK? I understand that this condition makes sense because the horn is stuck on. But it don't understand if further conclusions can be reach based on test condition 12 to ground always having continuity at this point.

Thank you again.

-k

 

If pin 12 there ohms out to ground then your fault is in that direction. Is there not a single relay anywhere for the horn? I might be thinking of a different car...