Intermittent Horn with Ignition Off

[RockBit]

While working in the garage where my Cobra is, I occasionally hear a low, short sound from the horn. This is with the key off. It doesn’t do it very often, but it is definitely there. Everything on the car works perfectly.

What could be causing this?

[strictlypersonl]

I've never seen a relay go flaky this way, so I'd suspect the horn switch/button (Lucas!) on the dash. Disconnect both the #11 wires from the switch and see whether the condition stops. Also, follow the pink wire from the switch to make sure that it's not being pinched somewhere.

[tgandy]

By any chance did you name the car Christine?

[RockBit]

Originally Posted by strictlypersonl

I've never seen a relay go flaky this way, so I'd suspect the horn switch/button (Lucas!) on the dash. Disconnect both the #11 wires from the switch and see whether the condition stops. Also, follow the pink wire from the switch to make sure that it's not being pinched somewhere.

Thanks Bob. I’ll check it out and report my findings.

[Ron61]

If the sound is so low it may be doing it when you are driving and you just can't hear it. That sounds as if it is getting a low voltage feed from somewhere. If the switch is good then check the hot lead to your horn and look for some place it may be touching a wire that is hot all the time just enough to let some voltage through. A relay sticking would normally let the full voltage through but that is another easy thing to check so don't ignore it.

Ron

[RockBit]

I have only heard this one more time after spending many hours in the garage. At this point I am going to wait until it gets more frequent before trying to find the problem.

Thanks to all for the suggestions.

[66AC]

IMO, Ron61 is spot on.
The circuit is rather simple.
Positive -> Horn Button Switch -> Horn Relay -> LOAD (Horns) -> Ground Negative

Either the Horn Switch is bad and making an ON condition in the circuit
OR
the wire from the Horn Switch to the Horn Relay and then to the LOAD (horns) is somehow intermittently touching some other positive wire causing the horns to sound briefly.

I would start with the Horn Switch.

I would remove the Horn Switch and test it with an Ohm setting on your Multimeter.

This Horn Switch is not very expensive if it is like mine. (a small push button on the dash).
So you may want to just get a new one and replace that switch.

It also could be a flaky Horn Relay? and/or the wire from the relay to the horns (33 Violet).