horn honked by itself,,all night long...ghost???

[boohoo222]

what could make the horn start honking in the middle of the night , no one in rv, all my neighbors were burning up my phone mad, any ideas

[Rickf1985]

That would be caused by the wire coming from the horn to the steering wheel being shorted out. My guess would be a mouse of squirrel has chewed through it and shorted it out somewhere. Unless you have an alarm system that has malfunctioned.

[DRMousseau]

And if ya see no obvious "critter" damage, or apparitions hangin' about... check out that horn relay.

While it might look good, internal corrosion can be hidden within. Weather changes of temp and humidity can have a great effect then. Mine was a solid rock inside!!! I figure the PO must have had a similar problem, and re-wired a mess! By the time I got to fixin' it all, the horns were also badly corroded inside, and had to replace them too! I ordered a new turn-signal/horn switch too,... but never used it after pulling the steering wheel and finding everything ok in there.

A pretty simple circuit to trace,... except pullin' that steering wheel.

[boohoo222]

how could I find out if I have an alarm system

[joanfenn]

I know on my jeep you can turn off the alarm by turning on the ignition with the key.  ha ghosts :)rotflmao ,

[Rickf1985]

Do you have a flashing red light on the dash anywhere when stopped and shut off? That will usually indicate an alarm. If you have one there will be a disarm button somewhere within reach of the door but installers can get real creative wit that since thieves can figure out the usual places easily. In order to disarm you usually have to turn the key on and then push the button within a couple seconds. When the horn blows does it do so for several minutes and stop and then do it over again for the same time period? Or just short, random bursts?

Timed duration's are going to be an alarm and short random bursts are going to be a short of some sort. Unplug the horns for immediate relief but if it is an alarm then the vehicle would normally not start while it is going off if it is a decent alarm. An alarmed vehicle will usually also have a decal on a window indicating it is alarmed.

[boohoo222]

neighbors told me it was a continuous horn for hours- like holding the button down and not letting it up

[Rickf1985]

Not an alarm, an alarm would be honk, honk, honk. That is a short in the horn wire somewhere. This could also be a fault in the horn button on the steering wheel but very, very unlikely since it happened when nobody was near it. The bad part of this is that if that wire was chewed by mice then others were too. If a hot wire was chewed ahead of a fused circuit you could have a short resulting in a fire. If there is nothing visible then you need to start jiggling wires and see what makes the horn blow, or if you cannot make it stop then unplug the horn and hook up a test light to the horn wire and that way you can just watch for the light to go out. Light on then horn would be blowing, light off and horn would not be blowing. NOW, Here is how I would do this. Have a helper and loosen the ground terminal on the battery. Disconnect the house batteries for now as a safety precaution. Loosen the ground terminal on the chassis battery so that you can pull it off by hand in a hurry if need be. have one person standing there ready to do just that. They may also be able to see the test light for the horn if you are hooked up that way and can holler when it flickers or goes out. Now start jiggling wires and when the horn starts reacting then start to narrow it down bit by bit to less wire you are moving to get a reaction and eventually you should be able to see where the problem lies. The reason for having the helper stationed at the battery terminal is in case there is a shorted hot wire and then you can pull the terminal quickly before damage is done. If you find the horn wire was chewed be sure to check ALL of the wires in that area to see if any others were damaged.

[legomybago]

Quick story....

The Father in Law had a neighbor, who's car alarm would go off at random times for no reason. And the neighbor always took there sweet time turning the alarm off. Well, one weekend when the neighbor was out of town, the car alarm came on early in the morning..honk!, honk!, honk, honk!....So the Father in Law called the police to see if they could turn the alarm off somehow? The cops showed up and said there is nothing we can do about it. So the cops leave, the horn is still honk!, honk!, honk!....The Father in Law went to the garage, grabbed some tools, and popped the hood open, and cut the alarm wires!! Ha Ha, no more misc alarm going off for no reason in the middle of the night!!! And of course this car was only a 1,000 dollar vehicle.... Moral of the story, if you have alarm issues, don't make it everyone else's issue.

[DaveVA78Chieftain]

   
• Steering wheel side of the horn relay circuit is a path to ground (black wire from horn relay).  Any short to ground from relay to horn button will cause the horn to honk.
• Orange wire from horn relay is B+ from fuse panel (This B+ is not switched via ignition switch so is always available).
• Green wire from horn relay goes out to horns.

While we do not have the 80-81 P30 chassis wiring diagram, we do have the 83 P30 wiring diagram in the Members area.   The 83 horn circuit (pdf page 25) should still apply for 80/81.

[sasktrini]

Sticky horn relay?

[Rickf1985]

Sticky relay would not energize itself.

[DaveVA78Chieftain]

However, the contacts could fuse together but that is rare.  Usually, the plastic melts not allowing the contacts to mate up.  Had a big problem with plastic melting on a fan relay in my 1992 Lumina APV (bad wire connector resulting in high resistance ergo lots of heat).

[DRMousseau]

Does your horn now function as is it should? normal like?

Or since this incident, is now not working at all??? Or perhaps it now works weakly or jus blips a little???

In most vehicles of this era, there's typically only three main components,... horn switch, relay, and horn.

While I still won't rule out a li'l rodent problem, I'm really thinkin this is a weather related incident. Corrosion inside the relay isn't unusual,... I've seen it far too often, and their a cheap easy replacement. Humidity, moisture, and temp changes can saturate the corrosion inside and make a good circuit. IF, the corrosion dries out a bit,... then it can quit as suddenly as it began. It MAY, or may not function as normal after such an incident,... mostly depends on how damaged the internal connections, relay coils, and contacts inside the relay are, because of the corrosion.

The connections and contacts of horn switch itself, is also somewhat prone to a bit of corrosion occasionally. This is sometimes seen as a "sticky" or uneven horn button,... works when pressed on one side but not the other, or not at all. Sometimes a "grinding scraping" sound inside this area, when turning the steering wheel back and forth, signals a problem here. I hate pullin' steering wheels, so I look here last, unless I find that "scraping" sound to be present. The nature of this switch, is such that doubt that temp and humidity changes are an issue in this area,.... it either works, or it doesn't, or your beating it cause it doesn't work good.

The horn too, is subject to internal corrosion and failure. Although it needs power supplied from the battery THRU the relay!!! If power is present at the horn terminal and it's well grounded,... it either works or it doesn't! And this doesn't seem to be your issue. LoL!

Look for a shorted wire in the primary circuit (critters, worn or broken insulation) or replace the relay,.... it's not sticky, it's shorting because of corrosion.

[boohoo222]

thanks everyone will start eliminating

[boohoo222]

well I found the problem, because of problem in my chevy s10, yep you guessed it, the horn in s10 started at 1 am, found chewed wires, so looked at wires on hr and found chewed wires and rat nest, so I fixed them and got a CAT, no more chewed wires