Thread: Horn issues

Hello All,

Just wondering if I have an earth issue with one of my Series III ute's horn? The horn is loud and clear with the ignition switch turned off. When I turn the ignition on or any of the lights and press the horn its sound is reduced to a slight "donk" noise. When the lights or the ignition switch is turned off the horn sounds loudly again.

Apart from maybe insufficient earthing to the horn does anyone else have an idea what could be affecting the horn when it has to share the electrical system with other devices feeding off the system?

Kind Regards
Lionel

if you dig out your circuit diagram in the series 3 workshop manual you can see the horn is locally earthed with a switched supply. it is possible that there is a bad joint somewhere that is now allowing enough current through to power the horn when ignition/lights are on.

a good place to start would be to chase down the supply for the horn switch. ive found it to be a thinner seperate wire coming from the indiciator/lights switch which will either connect onto the fuse box (or on the diagram it says the back of ignition switch). try to identify if a solid 12v are there at its supply when you press the horn and it DOESNT sound properly. (i.e. when ignition is on)

from here you should be able to chase where the problem lies either forwards through the switch into the sounder or backwards through the fuse box etc.