My car horn goes off at 2:30ish this morning - need help!

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Lifer
Jul 11, 2001
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I'm in pretty deep sleep and am becoming aware that a car horn is sounding. Actually I wasn't aware of that, what I was aware of was that someone was calling me on my landline. I'm thinking, what robocaller would call me at 2:30AM? I then hear the caller leaving me a message and it's my neighbor saying my car's horn is sounding. Then I'm aware that the horn is sounding. I pick up the phone and we chat a few seconds, 2 or 3 minutes later we are outside, I raise the hood and he ratchets the negative battery cable off. It's a residential neighborhood, 2:30AM, whew! Neither of us knew how long the horn had been sounding. He'd been sound asleep too.

He figured the horn fuse is inside the car, not under the hood. I'm not so sure. Anyway, I figured (guessed) it's the relay that's not working right. I have the Chilton manual.

Car is a 1997 Mazda 626LX 2.0 liter with less than 35k on it. I've had very little trouble with it, driven it less than 1500 miles/year generally, and less than 500 during the pandemic. I'm starting to play golf again, so will put more miles on it, maybe averaging 30 miles/week.

Other than the golf I've been driving 10-20 miles doing an every other week shopping run, centering around Costco.

I was planning to drive to a 4th of July birthday party today. Oh well, may have to miss that, depending. I figure I could go with horn disabled, but I suppose that isn't legal, don't know, but I'm a really safe careful driver and imagine I would NOT miss my horn, I almost never use it.

So, looking online: I see that it's probably either a bad horn relay or one of the two horn buttons on my steering wheel suddenly is stuck on.

I figure check the relay first. Are those just plug in units? Pull out and push in? Buy a replacement and see if that fixes the problem? I could bicycle over to O'Reilly's.

This car has airbags. Well, I guess not side airbags, but front. I have no idea if they would work. Online troubleshooting a stuck-on horn it says to be aware of potential complications because of installed airbags.

There's something else: There's a car alarm that was installed at purchase, a Crime Guard unit. They have life-time warranty. There's an on again off again issue with the alarm not working. The remote opens and locks the doors OK either way. I have called Crime Guard a few times and was told it's quite possibly a wiring problem, i.e. a bad connection. I suppose this is unrelated to the horn going off. The car alarm started working again around 3 months ago out of the blue and a few weeks later stopped working and it's been that way since.

I had a pretty good mechanic, but he retired 10+ years ago. He worked independently after a while in a nearby shop. I found another mechanic who was good, had a crew of around 4 guys, all certified in AC (my AC had stopped working). I had them fix the AC and next week had them do my 30k service, although I was maybe a couple thousand miles short of 30k at the time. The owner retired maybe 2-3 years ago. I called a recommended shop maybe 2 years ago and was told they won't work on cars as old as mine. I suppose I have to find a good mechanic who will or just sell the car. The state will give me $1500 for it to get it off the road, but fact is it passes smog exams with flying colors. It's not a polluter. Mileage not so hot at maybe 20 mph average.

Maybe pulling the horn fuse I can at least drive a day or two before fixing the problem.

A few minutes after disconnecting the battery and starting to become fairly awake, I realized that since I was planning to use the car today I should make sure the battery wasn't depleted. Multimeter said it was at 12.46v, which is probably OK, but drained a little. I put one of my chargers on the disconnected battery. It's still dark, figure to take a look to find the horn fuse after it gets light.

Moved from OT.
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deadlyapp

Diamond Member
Apr 25, 2004
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Wrong forum, but I suspect it's the alarm. Not sure why you think it is unrelated, car alarms drive the horn usually.

Personally I'd pull the fuse or relay for the horn and be done with it. The right way would be to rip out the alarm system and make sure everything is OEM or have a pro install a good alarm system.

Your car is nearly a hundred years old, it's not worth sinking any money in for a nuisance
 
Nov 17, 2019
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My '96 Sebring did the same thing. Parked it in the garage one day, later on I heard the horn blowing. Pulled the horn relay and it quit. Left it out. Tried it a few times and figured is was in the steering column which I wasn't about to mess with due to the explosives.

No inspections here, so never needed to pursue it further.

Forgot about it when I sold it a while back.
 

Muse

Lifer
Jul 11, 2001
36,943
7,818
136
Wrong forum, but I suspect it's the alarm. Not sure why you think it is unrelated, car alarms drive the horn usually.

Personally I'd pull the fuse or relay for the horn and be done with it. The right way would be to rip out the alarm system and make sure everything is OEM or have a pro install a good alarm system.

Your car is nearly a hundred years old, it's not worth sinking any money in for a nuisance
OK, yeah I know, Garage, but I was impatient BECAUSE I have been planning my 4th of July outing for a week and this threatens to all but scuttle it, so I figured, hey, a high percentage of the people who hit ATOT (which gets 10+ times the traffic, probably a lot more) are conversant in automobile technology and would very likely miss a Garage post.

My car alarm does not use the horn, it's one of those songbird alarms, you know, honk, squeal, arooma, bark bark bark, repeat. I don't think a horn can do that stuff. I don't know where it is, I was looking again a few days ago, prodding this and that trying to get a discontinuity to get continuous, since that's what the Crime Guard guys thought was happening.

I doubt that having the car alarm fixed would solve the horn issue but figure they would be able to handle that, so bringing it in to someone to fix the alarm is one of the things that crossed my mind this morning. I spent a couple of hours pouring over my Chilton manual and reading websites on horn won't stop issues before going back to sleep... I needed a few more hours to face the day. Thanks for posting!!!
 
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Muse

Lifer
Jul 11, 2001
36,943
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My '96 Sebring did the same thing. Parked it in the garage one day, later on I heard the horn blowing. Pulled the horn relay and it quit. Left it out. Tried it a few times and figured is was in the steering column which I wasn't about to mess with due to the explosives.

No inspections here, so never needed to pursue it further.

Forgot about it when I sold it a while back.
I wouldn't mess with the steering column, the explosives for sure being the main reason. Also seems real complicated. Maybe isn't but I've done a bunch of car stuff but messing with the SC sounds damn intimidating.

I figure tap the battery terminal with the cable and see if the horn honks. If it does, pull the horn fuse, which I think I can find. Looks like there may be two horn fuses, the Chiltons is damn confusing. I have never messed with the fuses. Looks like there's several boxes, also more than one for relays? Relays in fuse boxes too. :rolleyes:
 
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Muse

Lifer
Jul 11, 2001
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I wasn't up for watching any videos on this at 5AM, but now, after a cuppa coffee (and a couple more hours sleep), I just watched this 4 minute gem... it's real good!!!


He even shows you how to get into the steering column, on air-bagged vehicles and troubleshoot and fix a stuck horn button issue.
 
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mindless1

Diamond Member
Aug 11, 2001
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I wouldn't mess with the steering column, the explosives for sure being the main reason. Also seems real complicated. Maybe isn't but I've done a bunch of car stuff but messing with the SC sounds damn intimidating.

I figure tap the battery terminal with the cable and see if the horn honks. If it does, pull the horn fuse, which I think I can find. Looks like there may be two horn fuses, the Chiltons is damn confusing. I have never messed with the fuses. Looks like there's several boxes, also more than one for relays? Relays in fuse boxes too. :rolleyes:
It's safe to work around the air bag if you simply disconnect the battery and wait a minute for the capacitor to drain.

Can you find the manual or install guide for this alarm system? I too, would wonder if it's tied into the horn and would either remove it, or redo the wiring, as the alarm system wiring was probably dodgy to begin with (and you mentioned already having problems with it) and will get worse the older it gets.

I doubt it's the relay because a relay that is off, doesn't tend to turn itself on when it fails. Either it stays off, or sticks on when deliberately triggered. If it were a solid state relay using a transistor, this is a different matter but in '97, very unlikely to be solid state rather than a normal electro-mechanical relay.

Rather than Chilton's, there may be fuse/relay box diagrams in the owners manual, or a workshop manual. '97 was a generational changeover year, so it wouldn't be surprising to see two different fuse/relay box diagrams for same functions for '97. If yours is more like a '98 than a '96, you could seek the diagram for a '98, or vice versa.
 
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Muse

Lifer
Jul 11, 2001
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It's safe to work around the air bag if you simply disconnect the battery and wait a minute for the capacitor to drain.

Can you find the manual or install guide for this alarm system? I too, would wonder if it's tied into the horn and would either remove it, or redo the wiring, as the alarm system wiring was probably dodgy to begin with (and you mentioned already having problems with it) and will get worse the older it gets.

I doubt it's the relay because a relay that is off, doesn't tend to turn itself on when it fails. Either it stays off, or sticks on when deliberately triggered. If it were a solid state relay using a transistor, this is a different matter but in '97, very unlikely to be solid state rather than a normal electro-mechanical relay.

Rather than Chilton's, there may be fuse/relay box diagrams in the owners manual, or a workshop manual. '97 was a generational changeover year, so it wouldn't be surprising to see two different fuse/relay box diagrams for same functions for '97. If yours is more like a '98 than a '96, you could seek the diagram for a '98, or vice versa.
Ah, oddly the Chilton evidently doesn't have electrical schematics for the '97 626LX 2.0L. Has 25 or so others. The manual supposedly covers looks like 2 dozen cars or so!

Well, I touched the cable to the negative terminal of the battery and horn did not sound. Seems to be "normal" now. What you say about the relay probably working goes against my supposition, which was probably wrong. I figured to swap horn relay and hope all will be well. I will have to rethink all this, reread your post, etc. I could not find the horn fuse with the help of the Chilton or the owner's manual for the car. I will have to search the internet, maybe get ahold of the service manual for the car if I can find it.

Meantime in ~1/2 hour I will drive to the party, which is maybe 7 miles away? Have to program it into my android phone GPS app (Google) and see, have never been there... will keep my fingers crossed the horn doesn't go off. I'm sure not going to touch either of the two horn buttons on the steering wheel. I am going to take a socket set and pliers to be prepared to pull what I'm 95% sure is the horn relay or disconnect the battery if it isn't.
 

Muse

Lifer
Jul 11, 2001
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If all else fails you can just unplug the horn.
Yeah, that video has that guy showing that. He said, IIRC, that most cars have two and you have to unplug both if you go that route. But he had the car up on a lift so he knew easily where it is. I could find, but would have to crawl under the car, I figure, slide on a piece of cardboard.

I went the 15 mile round trip to the party this afternoon, no noticeable issues. Fingers crossed, but something's wrong and it's apt to not be the end of it... yet.
 

Muse

Lifer
Jul 11, 2001
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Yeah, that video has that guy showing that. He said, IIRC, that most cars have two and you have to unplug both if you go that route. But he had the car up on a lift so he knew easily where it is. I could find, but would have to crawl under the car, I figure, slide on a piece of cardboard.

I went the 15 mile round trip to the party this afternoon, no noticeable issues. Fingers crossed, but something's wrong and it's apt to not be the end of it... yet.
It's been 11 days and I've driven the car 4-5 times, the horn has not sounded. I tapped a horn button, yes it works. I figure whatever went wrong will happen again somehow. But a thought crossed my mind. Could a bug have crawled into the relay and shorted it at 2:00AM July 4th? If so, maybe it won't happen again.
 

mindless1

Diamond Member
Aug 11, 2001
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Relays are typically sealed or some have a tiny hole in the corner with tape over it for the system integrator to choose whether it's vented. It is unlikely a bug crawled in there, I'd think more likely a spider made a conductive web on the back of the relay box contents, or some other unrelated cause.
 
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