I have a 2004 Cooper S with a horn that stopped working. I have checked the fuse (and tried another 15a one) and still no sound. I hear a click from the fuse area when I press the horn, but no sound.

Also, I noticed that the temperature sensor on the computer reports -40 which seems a bit cold for the area I live in...heh...

Anyone ever have similar issues? I'm stumped, and haven't had a chance to take the car to the dealer, but want to at least get the horn working...

Jeff.

 

A failed relay will often make a clicking sound

according to the wiring diagram I have, the horn relay is in the pass' compartment fuse panel

You can sometimes free up a stuck relay (or solinoid) by tapping it....can't hurt.... you might just pull it out...tap it on something and reseat it and see what happens. Relay should only be a few bucks and may even be generic enough to replace via any autoparts store....but I never pulled mine to look see. There are, unfortunately 4 relays in this fusebox and my diagram does not label them, altho the key says it is relay 'a' if there are labels (my car is not here so I can't look). Perhaps you can determine which 'clicks' as you tap the button tho.

The temp sensor for the computer is behind the lower grill on the S, a bit to the driver's side. Have you ever had the front bumper cover off? Possible you dislodged the sensor? To remove the bumper cover you would remove the sensor ... if this wasn't done or the sensor was otherwise dislodged from the wire it is possible the system sees a 'zero' input resulting in the lowest reading possible ... but that's a guess. Find the sensor and look for damage.

 

-40 is a default reading. You may have your sensor damaged or wiring damaged. You would need a T30 bit, 8mm, 10mm, and a screw drive to remove your bumper.

With your horns it is possible that they both went bad. If you remove your bumper check the connection at both horns. They might have been left unpluged when someone damaged your sensor.

 

Has the front bumper been off - or something been going on up front?

The bumper cover comes off w/out getting close to the horn wiring; but is a likely cause of the temp sensor problem .... but begs the question why was it off.