95 850GLT Horn going off for no reason

[viper69]

Unless there have been some sort of modifications there is no horn relay. If it has been modified with some sort of aftermarket alarm that added a relay you are pretty much on your own to sort it out. In the case of aftermarket "upgrades" start looking at where the original wiring harness was butchered for tape that fell off or chaffed wires.

...Lee

Hi Lee, I have no aftermarket mods of any sort, save a CD player in the trunk.

I'm not really sure what he meant by horn relay to be honest. It was 10 mins before closing and the guy was doing too many things at once.

I may have to bring it to the Volvo dealership or a mechanic that specializes only in Saab and Volvo then. I've always found they know more about the oddities often encountered in both those brands IMO.

This guy does Volvos and other European vehicles as well as anything else, and may be too much of a generalist in knowledge perhaps.

[viper69]

Lately my horn has been working fine. Last night however, in the parking lot, I had turned the wheel and it went off at a very low volume. Then just lightly tapping the wheel w/the palms of my hands at the 7 and 5 position (like a clock) caused the horn to go off again a bit louder for a second two. It continued a bit as I tapped on/off to see if I could repeat.

I drop to the end of parking lot, it went off louder by itself.

Drove home, tried doing the tapping again, the horn didn't go off. No surprise as my horn problem is quite random, though only goes off at low speeds below ~35 mph.

Any ideas on this one, other than the stupidity provided by the user below? Thanks in advance.

[850TurboTurtle]

It helps to shout out "Go, my favorite sports team!"

Tutorial:

[viper69]

It helps to shout out "Go, my favorite sports team!"

Tutorial:

This was useless, thanks for wasting my time.

[abscate]

It's obviously either a short in the horn wire or a faulty switch in the wheel. I think I would disconnect the wire, tape end, and see if it stops to isolate the problem

[viper69]

It's obviously either a short in the horn wire or a faulty switch in the wheel. I think I would disconnect the wire, tape end, and see if it stops to isolate the problem

Thank you. I unplugged the horn itself under the hood when it was occurring a lot, no sound of course.

In disconnecting wire, are you referring to wiring w/in the steering wheel, or elsewhere? I don't know the wiring at all for the horn, thanks in advance.

This is hard to figure out according to my mechanic because neither myself nor he can reproduce the problem.

[polskamafia mjl]

It helps to shout out "Go, my favorite sports team!"

Tutorial:

This was useless, thanks for wasting my time.

I found that hilarious. That was well worth my time.

[abscate]

Okay, focussing on problem...

I'm assuming the Volvo horn works like most others in that the horn is activated by grounding a wire up at the steering column. If that wire is shorting to ground somewhere, your horn will toot intermitantly. You want to disconnect it as close to the horn switch as you can..I think you need to pull the wheel to do this

[viper69]

Okay, focussing on problem...

I'm assuming the Volvo horn works like most others in that the horn is activated by grounding a wire up at the steering column. If that wire is shorting to ground somewhere, your horn will toot intermitantly. You want to disconnect it as close to the horn switch as you can..I think you need to pull the wheel to do this

Ah I see now. I haven't changed anything in my horn, it's all stock. The only thing that was changed a few years ago was the horn itself. So the wiring should be the same.

Do you know how or by what wiring path the horn/wiring receives its power to actually sound off?

[regent]

The horn is fed +12 V all the time. In normal operation, when you push the "button" you complete the cirquit by connecting the negative to the horn.
You may have a dirty contact inside the wheel that is causing the intermittent honks, or the wire from the horn to the wheel may have been pinched somewhere allowing for an intermittent short to chassis.