1998 tacoma horn won't stop going off.

So I'm sitting on the couch and hear what sounds like a horn going off. So I go outside and the horn on my my 98 tacoma is just blasting away. I ended up disconnecting my battery. I just wanted to see if anyone had some insight into what would cause the horn to go off randomly by itself with the ignition off and the truck just sitting there. The truck doesn't have power windows or locks and does not have an alarm. anyone have any ideas?

 

I would think something in the steering wheel finally bit it. That's a strange one though, maybe we need an "Oddball Problem of the Month" thread.

 

Horn relay.

 

Likely this.
Even if it isn't, removing the relay to shut off the horn is better than disconnecting the battery.

 

Yeah^^^ i was gunna say the same. Remove the horn relay or the ground wire to the horn itself woulda been easier and ya still gotta do that now anyways when you hook the battery back up. Sorry if that sounded dickish, like you didnt know what you were doing...didnt mean it that way. Sometimes people are good at that on here from time to time.Pretty weird issue though. Musta been kinda funny when you realized it was your truck makin all the racket, lol!

 

My horn has a connector that you can unplug it from the wiring harness with (clips right into the horn). Probably yours does too so you can figure it out and not have your battery disconnected all the time / drive your truck until you get it figured out if you don't know which relay is for the horn yet - are they labeled? Hopefully it's an easy fix.

 

Well it was midnight. I was in underwear and didn't want to be standing outside trying to figure it out, so I just disconnect the battery. Woke up today reconnected everything and the horn works fine no issues at all??? I'm pretty much stumped.

 

If the horn relay gets worn & gets moisture in it, it can cause grime to build up on the contacts which will cause the horn to activate on its own.

 

Strange...

 

Your Tacoma is haunted. Perform exorcism immediately.

Jk, you just need a new horn relay. Check your fusebox and relay box for any visible issues.

 

My wife's old Mitsubishi did that, but only when the car was started on a cold morning.

 

Was there an aftermarket alarm installed?

 

This seems to be the most recent thread after a quick search, So this has happened to me a few times in the past couple of weeks. I too disconnected the battery at midnight the first few times. But I did end up pulling the fuse out.
However I noticed nothing wrong with the fuse for the horn/hazard (I think they are the same relay) So I put it back in and things were fine for a few days to a week then it happened again so I replaced the fuse although I could see nothing wrong. It happened again after the fuse was replaced. I did see it happening when it was rainy out more times than when it was dry.

Any thoughts? I can't drive without a horn in my area.

 

LOL - Use mine nearly as much as I use my blinkers - though I'm trying to be a little more subtler now and flashing my lights/brights nowadays.

I've can't comment on the nature of the problem. But watching 'cause I operate a '98 myself...

 

Fuse wouldn't cause the horn to randomly turn on. Your problem will be the horn relay, or contacts in the steering wheel. Change the horn relay.

 

if it is not your horn relay, check the steering wheel clockspring (also known as spiral cable)

when clocksprings go bad, they can cause horn problems, as well as cruise control problems and the airbag light to come on

 

Agreed, if not the horn relay, then its would likely be the slip ring shorting to something. Youll need to remove the airbag then the steering wheel to inspect it.

 

For future searchers, this is what happens when a relay gets moisture in it. This is the relay for my light bar. I was watching FMJ when one of the city guys stopped and told me that my light bar was on. Sure enough, when I looked, it was just barely on (probably about 1/4 strength).
When moisture gets drawn into an unsealed relay, it allows grime (dust also migrates inside) to build up on the supply contact. With enough buildup, the output side begins to get power. While it does not provide full power, it does supply some power to whatever the relay feeds.

This is during cleaning of the contacts.


Contacts cleaned. Notice the bar is toward the outside. Open circuit position.


I am holding the bar into the closed circuit (activated) position. If there is buildup, it will basically bridge the contacts.