Need HELP! Horn works in reverse!
 

Recently, I bought the 2nd hand '01 Boxster S. After finalizing all the deal, I enjoyed the car very much. Then, I realized something very strange.

When the key is out of ignition switch, horn works. If I put it into ignition switch and car starts, horn doesn't work?!! Very dangerous!!
It should work in reverse, right? Horn should work in driving!!
I thought the ignition switch was the problem, and I replaced it with new one. But, it didn't fix the problem. Does anyone know or have good guess on what happened? Thanks for your help in advance~! Happy boxstering!

John,

Hi John:
The only thing I can think of (other than the previous owner rewiring the horn) would be the electrical portion of the ignition switch.
This switch controls most of the electrical components in the car and when it starts to fail it can cause all sorts of gremlins.
The strange thing is that it generally causes more than one electrical symptom.
Do you have any other electrical issues?
Happy Boxstering,
Pedro

Hi, Pedro!

Like I explained, I don't have any issue other than horns. It was very nice meeting you, Pedro! You save me the other day!! I will see you soon.

John,

It sounds like you have a problem at the ignition switch, these switches are made of plastic and they get damaged commonly, it is located right where you insert the key to take it out you have to go under the dashboard and it is a pain in the ### you should get your car at a electric mechanic to check it out for you, I replaced mine quite some time ago and have no problems since then...
happy boxtering !!! :cheers:

If the emergency flashers work with the key on, then check the horn relay for proper operation.

Another thing to look at...
 

... is the ground wire to the horn plate.
You'll need to remove the airbag, since the horn plate is the airbag's base.
Disconnect the negative side of the battery.
Make sure that the key is NOT in the ignition.
From behind the steering wheel loosen the 2 torx screws that support the airbag.
Disconnect the airbag and set aside.
Check the brown wire connected to the horn plate.
If it disconnected, that's the problem.... no ground.
If it is connected, check continuity against ground.
Re-assemble in reverse order.
Happy Boxstering,
Pedro