Wassup! I have 04 LS430. Recently the horn has been sounding on its own. I've noticed that it occurs more often in the morning when it's cold and when I make turns. It sounds like its being pushed like 5 plus times randomly while I'm driving.

Also on a few occasions the horn would go off continuously while parked. The only way I can stop it is if I press the horn to turn off.

Note: My smart key stopped working so I've been manually opening the door until I make it to dealer for new key. Not sure if this may be a cause or perhaps a bad connection somewhere. I'm gonna pull the horn fuse if this continues but wanted to know if this has happened to any of you.

Your feed back is appreciated!

 

Pressing the horn button to turn it off indicates to me that it is a stuck switch.
I do not think that it is a "toggle" type of function.
Hope this helps.

 

I have personally had the CLOCK SPRING go out on my high-mileage Saab (I know – this is a Lexus site). The symptoms were that the horn would not work while depressing, or it would occasionally beep randomly while driving. The steering wheel spins in a circle and needs to be able to make constant electrical contacts with its controls. The CLOCK SPRING is a wiring harness that has pins/contact that are pushed up against the steering wheel contacts (metal rings) via springs. With age and use, the contacts wear out thereby sticking, shorting, wearing down, etc. As it got worse, the ABS light came on as well since those contacts were failing too. I had the dealer replace it for < $350 parts and labor, but different threads talk about it possibly being a DIY for less. Back to normal operation! Good luck; be safe.