Yesterday I discovered the horn(s) weren't working on my 3.7 Roadster. I have now removed the horn push in the centre of the MotoLita steering wheel - cleaned up the copper contact strip and tested the circuit when the button is pressed in, which is all working. I have also removed the 2 horns, cleaned up the connectors and tested each one individually - both working fine.
When the engine is running they work as they should, however if I have the ignition on, but no engine running, they don't work. I can hear them trying to make a sound, but not properly. Are the horns meant to work with just the ignition on?
I suspect there may be a corroded earth somewhere? I can see on the Roadster circuit diagram that there is a wire that comes off the junction of the horn wiring to a chassis earth with a 5mm eyelet, but I can't locate it. I have tried tracing the wiring from the horns right back to the fuse box, with no luck. Does anyone know where this earth is located?
Thanks in anticipation.
Seems that the voltage getting to your horns is not enough with just the ign switched on, but rises when the engine is running and the alternator is providing charge enough to make the horns sound as they should... If the battery can spin the starter motor enough to fire up the engine, then it seems it should be capable of sounding the horns too, which then perhaps points to a relay, assuming one might be fitted in your horn circuit...? Fortunately other than for an MOT, the only time you really need a horn is when the engine is running...
Wishing you all the best in finding a quick answer to that one...
