Horn melted off of my LC!

[slider35]

So I get a call today at work from my neighbor telling me that alarms on my house are going off and I should probably come check it out. I get home to find no alarms tripped and really nothing out of place by the appearance of things. I talk to a few neighbors who heard the loud, annoying "alarm" for the better part of the afternoon.

Well after investigating, i opened the hood of the LC and was hit in the face by the smell of burnt electronics. It didn't take me long to find the problem. The horn had begun to melt off of it's bracket. Luckily the fuse blew and saved me from much bigger problems.

Now here's my dilemma. The voltmeter is still reading 12.6 at the horn fuse. I pulled the horn relay hoping that would be my problem. Nope. Still reading 12.6 with the relay pulled. I don't have a wiring diagram to look at. I'm comfortable working with electricity. 12v, 110, 220, I understand the basic theories, but this issue has me a bit worried. I don't get a good feeling thinking about tearing into the steering column. Anyone have any ideas for me?

This is my 2000 LC. All I know is that it was sitting in the drive and the horn just started blaring in the middle of the afternoon. No aftermarket alarm on it. I don't have a clue what might have started this.

 

[MEMCruiser]

I have a horn problem also on my 98 LC. The horn did not work, so I checked the fuse. Fuse was bad, so it was replaced but horn still did not work. The horn relay did not match the relay that was in Toyota FSM. I pulled horns and connected directly to battery and did not work. Not sure if they broke from normal use or from another problem. I have not replaced them to see if they will work normally.

When I first bought the car 6 years ago my neighbor called at 3am telling me my horn was blowing on car. I took it to mechanic and he fixed it but not sure what he did. That was before I got the bug and did not give a s*** then.

 

[LCHardriver_02]

It sounds like you have a short with a separate power source (non horn related) to the load side of your relay wiring. I don't have my FSM in hand to look at the schematic. I can look later tonight, when I get home, but my initial thought would be that somewhere on the load (horn) side of the relay connection there is a short to a non-switched power source. Could be power coming into your steering column for the ignition switch, or lights for that matter. I would start checking for shorts (ohm meter) to other circuits local to the relay location, with the relay removed. As you find them, remove their source of power (fuse, relay, etc) until you narrow it down to the culprit.

Good luck,

Jonathan

 

[ginericLC]

I can't remember for sure but doesn't the horn relay work on a ground rather than applying power to it. The horn button acts as a ground allowing the relay to act instead of the relay getting a positive charge. At least that is how I thought it worked but I could be wrong.

 

[LCHardriver_02]

Eric is correct about the relay functionality, as it closes when the horn switch is depressed, applying a ground, but since the horn is powered with the relay removed, then you have a short where the relay switch should be opening. I would check the relay base, as it has the highest potential for being your problem child.

Good luck,

Jonathan

 

[slider35]

Thanks for the posts and suggestions. I'm going to spend some time on it over the next few days. Wish me luck.

There's also some speculation by my neighbors that it may have been hit by lightning, but I don't see any evidence of that on the outside of the LC anywhere.

 

[LCHardriver_02]

I would doubt the lightening strike idea, but it would make for a great story afterward!