Topic: Disappearing Horn Voltage

[Bill Vaughan]

75 CB550 (K1).  Stock horn/harness.

Horn sounds loudly when connected directly to the battery at 12.5 volts.  Voltage at the horn harness connection points is roughly 11.7 volts when the switch is activated.  However, when the horn is connected and the switch depressed, the voltage disappears and no sound can be heard from the horn.  Adjusting the contact screw makes no difference.

Any ideas as to why the voltage would go down to zero under load?  Bad switch contact or ground, perhaps?

[D-Ral]

Having a similar problem. Black and light green wires get over 12V, but black and green from the switch when button is depressed gets .5V. I've traced it back to the switch, but I'm not sure where to go from there.

[Deltarider]

First of all: check if wiring is correct for your model [area code!]. The Owners Manual for my 500 came with no less than 4 wiring schemes for various markets and polarity of wiring (horn) differs. Maybe there's something similar with the various 550 models.Then check mass contact ofcourse.