Ford C-Max – (photo by Ford) Some of the common causes that stops the horn from working normally on your Ford C-Max are blown fuse, bad relay, faulty horn, corroded or worn out connector, broken wire, broken clock spring or bad horn button. 1. Blown fuse. The horn on Ford C-Max needs electricity to work. In case of a faulty fuse, the circuit 2016 Citroen Dispatch, the horn's stopped working. Has had recent alarm issues, may be related, but I hope not. The fuse box/BSI has a Horn fuse, which has blown. Replace it and it blows again. Disconnect the horn unit itself, replace the fuse, it blows again. Cigarette lighter fuse. Assignment of the fuses and relay Citroen C2 2003-2010. Fuse and relay location. Fuse box diagram. (15A) Horn: 14 (10A) Windscreen/rear I know you have a 1982 but the wire colors should be the same as on a 1980 Orange, Black & Dk.Green. Do a continuity check between the black of the 3 wire connector and a good known ground. You should have continuity when the horn button is pressed. Grounding the horn button is what energizes the horn relay coil. Horn Kaput. Usually it's the ground. 'Older' models utilized the physical ground where the horn mounts to the frame. 'Newer' models ('94 up, so I'm told) utilize a separate ground wire which is also grounded to the frame; DUH. Anyway, unscrew where ever the ground is, clean it up with sand paper or scotch bright, screw it down securely and give Consider to support my channel and all the hard work put into it at http://www.patreon.com/LMAutoRepairsThank youHiThis car come to me with the rear fog ligh Messing around with a 2004 Ion. The horn was not working due to a problem with the horn switch in the steering wheel. I ended up wiring in another switch in 2015 C2 of Year Finalist. There should never be 12 volts to the horn contact. The contact is the ground. The horn relay has a full 12 volts at all times. But no ground or the horns would blow all the time. When you press the horn button it completes the ground circuit allowing the horns to blow. Reply Like. H6yt.