My horn has stopped working and the airbag light is on the car is a 2002 206 any ideas and how much will it cost to fix?

I have a 206 cc and my horn stopped working it was a broken wire at the plug just under the front grill u can try and fix it ur self but if it is that u will need Peugeot to wire a new plug close to £100 sorry can help on the air bag