Horn sticking

H

HNTMUP

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Got a problem with my horn - it just goes off (like at 4:15AM this morning). Talked with my local mechanic and his initial thought is it's a bad "pad." Three questions:

1.) if this is the case, can the pad be replaced without having to replace the airbag?
2.) what's a ballpark price for relpacing the pad only (if I don't have to replace the pad and airbag)
3.) what's a ball park price for replacing both the pad and the airbag?

Any suggestions?

Thanks,

JDG
 
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This may not be the solution you want, but just disconnect the horn so you can take your time in finding a solution instead of going through a mechanic to get it fixed immediately.
 
Nelsonmd said:
This may not be the solution you want, but just disconnect the horn so you can take your time in finding a solution instead of going through a mechanic to get it fixed immediately.
Click to expand...

That's why I ask. He pulled the fuse so it's not going to go off again. Now I need to know what my options are from someone other than my local mechanic.

JDG
 
Nelsonmd said:
This may not be the solution you want, but just disconnect the horn so you can take your time in finding a solution instead of going through a mechanic to get it fixed immediately.
Click to expand...

X2

I'm not sure on the pricing on the pad, but I'm pretty sure air bags are expensive.

Do you have an aftermarket alarm?
 
Shoke said:
X2

I'm not sure on the pricing on the pad, but I'm pretty sure air bags are expensive.

Do you have an aftermarket alarm?
Click to expand...

Yes - airbags are VERY expensive (which is why I ask if the pad can be replaced without having to replace the bag).

No - I do not have an after market alarm.
 
Well, according to the FSM, the pad is just a normally open switch, so I think you should be able to test it with a multi-meter.

I wouldn't think it would be the pad. If the pad has an intermittent failure, then I think you would hear a sputtering horn more than a full-on. I would think it is an ECU issue.

I couldn't say if it is a bad ECU or if the ECU is receiving some bad stimulus to activate the horn.

Test the pad before you go replacing anything. It looks like you can tap the ECU lead for the wheel switch and ground for the test.
 

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Sorry to be so dense but what is an ECU?

I have not had any problems with the horn until last weekend when, while driving on a rough road the horn went off. I kind of pulled back on the housing and it stopped. Then Tuesday morning it went off twice while sitting in the drive where it had been parked for hours.

So, pad? ECU? Suggestions?

Thanks
 
ECU is the vehicle computer.

If you pulled back on the steering wheel housing and it shut off, then maybe the issue is with the steering wheel housing. It could be stuck halfway down or something like that. I think you are going to have to get in there and check it out, or test the pad like I said.

If you touch the steering wheel, pull the airbag fuse first. You don't want to set it off while you are working on it.
 
Nelsonmd said:
If you touch the steering wheel, pull the airbag fuse first. You don't want to set it off while you are working on it.
Click to expand...

That may not be good enough. The FSM says to turn key off, pull the negative battery cable, and wait 90 seconds for the reserve power cap to bleed down before working near any SRS component (and I will add: ESPECIALLY IF YOU ARE CHECKING RESISTANCE).

I wonder if the "clockspring" cable in the pad could be a suspect. Usually they fail to an open horn circuit, not to a short, but who knows? It only has to short to ground to set off the horn (true for anywhere along the wire between the pad and the B-ECU).

Anyway, read this before messing around in there. If it's still good, you don't want to break it.

Here's a suggestion--pull the plug out as described in the link and leave the clockspring disconnected. You will lose the horn, airbags, and cruise control. Reassemble leaving plug loose and replace horn fuse. If no midnight horn, problem is indeed pad/airbag assembly. If horn still goes off, then clockspring to B-ECU wiring is bad, B-ECU is bad, or wiring B-ECU to horn is bad. This last is extremely unlikely, as it would mean picking up stray key-off 12V+ somewhere and not blowing a fuse. Also, you haven't had a recurrence with the horn fuse pulled, so that means rogue current is passed by the B-ECU and not picked up by the wiring via some short.
 
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Horn turns on when the ignition is on

I wrote this in another post as well, but I don't see anyone with this exact problem and I can't put up new posts yet:

Anyone know how to fix this problem on a 99 T4R? My horn turns on and stays on when the ignition is turned to the on position. I've ruled out the clock spring by taking apart the steering wheel and testing that the wire is not grounded. The horn button works fine when the vehicle is off too.

Before this problem started, I pulled out the fuse box to check diagnose a problem with the wipers. That was resolved and I plugged everything back in. After that, I started the vehicle and the horn started sounding. It won't stop when the ignition is in the on position.

I'm thinking it has to do with the relay in the ECU or there's a wire crossed somewhere that's sending power to the horn. I don't have any alarm components on the vehicle, and this doesn't seem like the typical symptoms people are having with their alarms since the horn only comes on when the vehicle ignition is on.

Also, I pulled the horn fuse and it still comes on when the ignition is on. I think that's because there are two wires coming from the ECU: one to the horns directly and one to the fuse box. Pulling the fuse will only keep the horn button on the wheel from working.
 
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GG2000-4Runner said:
I wrote this in another post as well, but I don't see anyone with this exact problem and I can't put up new posts yet:

Anyone know how to fix this problem on a 99 T4R? My horn turns on and stays on when the ignition is turned to the on position. I've ruled out the clock spring by taking apart the steering wheel and testing that the wire is not grounded. The horn button works fine when the vehicle is off too.

Before this problem started, I pulled out the fuse box to check diagnose a problem with the wipers. That was resolved and I plugged everything back in. After that, I started the vehicle and the horn started sounding. It won't stop when the ignition is in the on position.

I'm thinking it has to do with the relay in the ECU or there's a wire crossed somewhere that's sending power to the horn. I don't have any alarm components on the vehicle, and this doesn't seem like the typical symptoms people are having with their alarms since the horn only comes on when the vehicle ignition is on.

Also, I pulled the horn fuse and it still comes on when the ignition is on. I think that's because there are two wires coming from the ECU: one to the horns directly and one to the fuse box. Pulling the fuse will only keep the horn button on the wheel from working.
Click to expand...

First off - you can unplug the horns from the single wire connectors. They are located just behind the front grill but in front of the radiator and A/C condenser. That at least makes it tolerable to yourself and other drivers.

The issue has to be related to something that changed when you removed the interior fuse box. Your best bet is to remove the fuse box again (yes, it's a pain) and reinspect all wires and connectors coming off the back. Look for damage or pins that have been pulled out by accident. Maybe you can do this with a mirror with it still on.

Did you disconnect the ECU or try and remove any relays from the fuse box? Many of the relays are quite stuck in place and will break if attempted to remove.
 
Thanks, gamefreakgc! That's what I ended up doing, and then it started smoking, but I didn't hear the horn. I saw the smoke and pulled the negative off the battery. Turns out the cover panel over the circuit board had bent one of those little metal terminals on the board and caused it to touch the one next to it. I bent the metal piece back and reinstalled everything. I don't know how, but the horn is working normally now; however, I now have a problem with the left blinker not working. It doesn't work with when I press the hazard button either. Going to work on diagnosing it tomorrow.
 
Very the fuse is good and check the circuit it was shortened to. :) you see smoke it's definitely a dead short.. :(

Sent from my SM-A536V using Tapatalk
 
GG2000-4Runner said:
Thanks, gamefreakgc! That's what I ended up doing, and then it started smoking, but I didn't hear the horn. I saw the smoke and pulled the negative off the battery. Turns out the cover panel over the circuit board had bent one of those little metal terminals on the board and caused it to touch the one next to it. I bent the metal piece back and reinstalled everything. I don't know how, but the horn is working normally now; however, I now have a problem with the left blinker not working. It doesn't work with when I press the hazard button either. Going to work on diagnosing it tomorrow.
Click to expand...

Good thing you noticed before anything else happened!! Smoke and wires, no bueno. Good catch on the terminal being bent.

I suspect a new fuse is in order. Don't bother testing or 'looking at' the fuse, just get a box of assorted fuses from the parts store, replace the blinker/side marker fuse and keep the fuses in the glove box. I suspect you might be chasing shorts for a bit and something else might blow.
 
I ended up mapping all of the blinker/hazards wiring and couldn't find a single short, but somehow I fixed the blinker issue. The only thing I changed when I put everything back to together was the relay, but I don't understand how the relay was malfunctioning since the right side blinkers still worked.
 
Reviving an old thread. (new account, can't make a new post)

My 3rd gen just started going off at 3am, removed the battery terminals to look at it in the morning, couldn't figure it out so I removed the fuse because I had to get back to school.

I ended up pulling the headliner down slightly as I had to reattach the rear sunroof drain hoses, lot of water leaking down the side of the car/A pillar/onto the steering wheel. Would something like that cause the horn to go off? And now I'm having this terrible battery discharge to the point that I have to jump the thing whenever I want to drive it.

Also, noticed some small gaps in the sunroof track from the inside (when I pulled the corner of the headliner to check the front drivers drain) so I tried sealing with silicone, and now water is leaking down in from the sunroof again (which I had tried fixing before by sealing the crack in sunroof trim with silicone).

So a lot of problems, but do they seem related? If anyone has advice for the leak problem, would love to stop my center console from being constantly filled with water when it rains lol.
 
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