Hi,

The horn in my 2003 R53 worked intermittently then stopped working altogether. I'm trying to fix it.

I basically leaped to the conclusion that my clockspring was bad and bought a used clockspring off ebay and it does the same thing. The horn doesn't work but all the other functions seem to work: cruise control, stereo volume, etc. I thought I heard a faint toot when I pressed the button.

Has anyone heard of the horn buttons themselves failing in R53s? As I recall one horn button seemed to stop working before the other. Is there any good way to test the button?

I started looking at testing the horns themselves but it looked like I'd have to remove the whole front bumper.

 

When mine quit working, I just assumed the horns were bad and replaced them with Hella Supertones. Problem solved.

 

Here's a picture of a non multi function clockspring. The green and black wires are for the airbag, so the other 4 pin connector must be for the horn.

I believe if I remove and disconnect the airbag like I did before and then disconnect this cable from its socket that I should see continuity on its wires when I press the horn button. Also if I reconnect the battery and jumper some combination of pins in this socket I should hear something from the horn.

 

Frankly, that seems like a lot more work than pulling the bumper cover and testing the individual horns.

 

I removed the bumper and horns and tried connecting each to the battery terminals multiple times using jumper wires with a alligator clips. The pins inside are so small it's hard to be sure that you are making good contact, but I did it enough times I'm pretty sure I would have done it right at least once. I didn't hear anything.

I also stuck some wires in the horn socket and had my daughter push the horn button and I didn't see any voltage on my multimeter so it looks like I have problems on both ends.

 

I removed the sockets from the horns which exposed a larger terminal underneath. I touched the terminals to the battery and got a brief toot out of one but bit the other. I've ordered some new horns.

 

That didn't fix it but changing my horn buttons did.