I have a problem with the horn on my 2003 307 Hdi Dturbo. Sometimes it works, sometimes it doesn't. I'm tempted to remove the central cover from the steering wheel to gain access to the contacts but am a bit reluctant to poke about without some advice, knowing that there's a an airbag under it. Does anyone know how to safely remove the cover? I assume it's clipped on and can be prized off. Any advice greatly appreciated. Steve