Horn Woes HELP!

[KDMatt]

'Was backing into the driveway, as per usual. Without warning the horn starts blaring and won't stop!

Quickly grabbed tools and dc/ed battery at positive terminal.

Reconnected battery, no horn. Car is now in driveway.

No casualties beyond a few disgruntled neighbors (seeing as it was 11 PM), a ringing ear, racing heart... and missed appointment with the Dukes of Hazzard county.

What has me stumped is that it didn't start blaring again after I reconnected the battery. Is there a solenoid or something that controls the horn?! (wtf?)

Somebody help me please, I don't want to wake up my neighbors again! :dead:

[zbane]

When you were backing up, perhaps you tapped the horn, maybe the spring that breaks the connection has become a little gummed up from time and didn't release right away, who knows.

Since it didn't start blaring after reconnecting the battery, I imagine it has something to do with the user connection, might be something simple, or so we can hope.

[KDMatt]

Hrm... well I didn't bump the horn... and for now I've pulled the horn fuse so it won't happen again (though this leaves me without a horn... very unsafe!)

I do seem to recall bumping the curb though. It was dark and I was backing in rather precariously. I don't remember feeling a jerk... but I don't suppose I remember much of anything... other than the quick shot of adrenaline as panic set in... I literally ran from the car to the house (for a flashlight) and to the garage for the tools... fumbled for the right wrench and popped off the terminal. That horn was going for about 5 minutes

...and... shoot... my custom settings on the stereo are probably lost now too. Damn.

Is it possible I've got some dirty grounds? I can remember a while back when I was on the freeway I held down the horn button as guy moved over and nearly hit me. As I did though, the horn seemed to cut out a bit. Instead of a long beeeeeeeeeep like I should have gotten... I got more of a beeeeep...bp-beep beeeeep

Related?

[zbane]

I think if it were a grounding issue, that the horn shouldn't sound when un-grounded. I think it's a problem with the connection, maybe the copper brushing IN the steering wheel is corroded. Then again, I'm no electrician.

[KDMatt]

Hrm... it's a possibility I suppose.

The steering wheel is aftermarket and... I would estimate 20 years old at that.

This is one of those moments where I'm feelin' the hurt of not having a FSM... if I had one I could trace the path of electricity to the horn and figure out where power could have seeped in if not a switch issue.

This has got me freaked out man. I don't want to be cruising down the road then all of a sudden BEEEEEP! ... that would be a very embarassing, albeit annoying way to show up to work. o.o

[zbane]

I don't know if any of this will help, keep in mind that I have a 280zx, some differences will be the case. You may have a horn relay switch in the engine compartment, near the battery, perhaps behind a removable panel. I'm searching my FSM for the other electrical.

[zbane]

I found the diagram for the zx, I don't know if it will help, but here is where the wires go-

horns (engine bay), engine room harness, horn relay (3 pin connector), combination switch connector (12 pins),line splits 1 line to main harness and on to fuse block, the other to another harness (10 pin) to combination switch, then on to the horn button and ground. I wish I had a scanner, this would be much easier.

[EScanlon]

There IS a Horn Relay, and if it's location is like in the 240's it should be on the passenger's bus box (that funny looking thing with all the relays, and other electrical boxes).

It wouldn't be unheard of for the relay to have gotten "stuck" and caused the horn to blow continuously, especially if for some reason the internal switch got "stuck". Remember it's more than likely the original relay (they don't go bad often enough to have possibly been replaced more than once). When you disconnected power, it broke the contact and allowed the electromagnet to loose the connection, that's why it didn't go off again when you reconnected power.

Check the relay, it should have H - S - B on the side or on the base. It's a 3 wire relay, and is generally about 2 to 2.5 inches long, 1 inch tall and about .75 inches wide.

FWIW

Enrique

[zbane]

how do you post a photo in these messages? I shot one of the horn electrical system.

[KDMatt]

Hrm... the relay sounds like the most likely suspect... HOWEVER... I will mention this.

After I reconnected the battery, I gave the horn a quick tap and it seemed to be working normally, no... "stick"age.

I'll still check the relay though... if I can find it.

Is it possible to pop it apart, clean it out/rebuild and replace, or is it something I have to buy a replacement unit of and/or find one in a boneyard?

EDIT: Zbane, you have to do an "Advanced mode" reply. Down at the bottom you'll see a "Manage Attachments" button. You use that to attach a picture.

[EScanlon]

Here's a link to help you:

http://www.atlanticz.ca/zclub/techtips/electrical.htm

They have wiring schematics on line, that unfortunately are too big to upload here.

You CAN open it up, but it might be just as easy to buy one at the parts shop. That it didn't stick the second time around, again isn't unusual. It may have been a fluke, or ....

FWIW

Enrique

[zbane]

from the FSM-

Horn does not stop to sound--

1. Short-circuited horn button and/or horn button lead wire.[when instrument harness is disconnected from combination switch, horn stops sounding]

2. Faulty horn relay.

"Corrective Action"

1. Repair horn button or its wiring

2. Replace (the relay)