Not on the button
QI keep getting an intermittent problem with my boat’s horn. It works at first but ceases after a few uses. If I remove the horn and put its contacts directly across a battery, it sounds. The horn is at the front of the boat, the battery at the back. Using a meter, I can get a voltage reading at the horn, so the button isn’t the problem. The long length of cable from horn to battery is suitably thick. Any ideas?
JEFFRICE, from the CB website
ATONY REPLIES... Although you say that the cable is ‘thick enough’ I would suggest that it might well be undersized, but to be certain we would need to check the voltage readings.
If you attempted to measure the amps a horn draws when sounding it would likely be about half that needed to actually start it sounding, so any loss of amps or voltage to push the amps through the horn could well result in your symptoms. If you add a bit of volt-drop along the cable with lower voltage from the battery(s) this is the sort of problem you can get. Sometimes the horn makes a single click and nothing else.