So about a year ago my wife clipped a dear on her way to work, 2009 Toyota Corolla. Got the repairs done, later on we notice the car horn isn’t working. So we have it replaced no big deal. Six months later it stops working again. Wife goes back to the mechanic, he just replaces it again. Not even six months later the horn stops working.
Or does it? I try it a couple days after and its working. I try it another day and it works but sounds a bit weak. Try a few days later and its not working. Fuses are all good, battery is good, wiring from the horn is good. I do not know how to tell if the relay is or isn’t working. No other electrical issues and I feel confident the other horns were fine but something sneaky is happening.
Anyone come across this problem in a Corolla specifically or any other vehicle?
Bonus Round: Are Corollas notorious for burning out Ignition coils or is it just ours?
Sorry, just can’t help myself, but I hope it was not a dear friend or neighbor that was hit, I have hit a few deer though and agree with checking the grounds.
Can’t remember the last time I used my horn though. I should probably check them to make sure they work. I paid extra for the dual tone horn when I ordered my park ave. Years later when the horn failed, I just bought a $10 replacement at the farm store. No one knew the difference.
The next time the horn doesn’t work, turn the ignition on to unlock the steering wheel, and then turn the steering wheel back and forth while pushing on the horn.
If the horn sounds there’s probably a problem with the clock spring.
Looking at it is all I have right now, I don’t have a voltage meter to test it but I do plan on getting one. I wasn’t there with my wife to ask them to test all that.
The horn circuit forms a loop, & for the horn to “honk”, all of the following must happen
someone has to press on the horn button
switch works
Main body ECU ok
Horn fuse ok
Horn relay ok
Clockspring wiring ok
Wiring harness & grounding ok
Battery voltage good
Has your shop measured the input voltage to the horn itself?
I don’t recall hearing that here much. A common reason for a failed ignition coil is the spark plug gap grows too wide. The computer compensates by increasing the voltage.
Ignition coil failure on 2007 - 2009 Toyota and Lexus vehicles is more common than with other vehicles. Ignition coil fault codes often observed are P0351 through P0356. Toyota vehicles use iridium spark plugs, the change in spark plug gap is insignificant during the life of the spark plug.
So I dont know if the shop measured the voltage, I wasn’t present. We troubleshooted the Clock spring, no airbag light, cruise control works and turning the wheel doesn’t make the horn sound. I am building as much information as I can to help them diagnose it better instead of replacing the horn again. I do plan on getting a voltmeter I just dont have one right now (Im a cop and I work alot lol).
You can test a horn either in or out of the car with a 12 volt power supply such as a spare battery or battery charger. If the horn works, it’s a wiring problem. If it doesn’t work, the horn is shot. Why? Who knows?