horn failure

kees · 04-27-2004, 08:28 AM

When driving my car, a 911 carrrera 1985, the horn fails to operate. When standing still, it works perfect. I've changed the wiper/horn contact and the slip ring, but it still doesn't work. Please help!

Kees.

djmcmath · 04-27-2004, 08:59 AM

Oh, that's the Rolling Horn Interlock, introduced in '84. It's designed to keep angry motorists from honking at one another while the vehicle is in motion. If you'd like to disable it, look in the Bentley's under "Rolling Horn Interlock" (I think it's page 620-12, but I don't have mine in front of me to make sure).

Ok, in all seriousness, that's a mysterious problem. Is there a speed that it stops working at -- can you roll slowly and still get the horn to work, and it's just failing at freeway speeds? I was recently under my own right fender messing around near the horns, and it seems that they'd be reasonably prone to looseness in the electrical connection at the horn itself. I don't suppose you've been up under the fender to inspect for damage?

Dan

Early_S_Man · 04-27-2004, 09:28 AM

Kees,

Pull the horn relay and check for corrosion on the pins or socket, or a loose fit. Substitute another round black, tan, gray, or red relay ... to see if the problem is the relay.

Check the condition of the Faston connectors at the horns ... corrosion or loose connectors are possible. After cleaning, crimp both sides of the female Fastons for a tighter fit.

wnsgc · 02-19-2007, 09:15 AM

Did you ever get a resolution to this problem? I just purchased an 85 Carerra and have the same problem. The horn works fine when the key is either not in the ignition or is in the ignition in the initial position, however once I turn the key to position 1, 2 or the car is running, the horn doesn't work.

emac · emac's Garage

Check for a loose connection behind the pad on the steering wheel

wnsgc · 02-19-2007, 10:08 AM

Ernie,

Thanks. I'll give it a try, but it seems odd that just the turn of the key will be caused by a loose connection. I literally can turn the key from position 0 to 1 and the horn cuts out.

I'll let you know what I find out.

Thanks for responding.
Scott

emac · emac's Garage

Scott
I could just be chance but when I first got my SC I had no horn, then I did, then when I didn;t want it. Key on or off just weird. I checked everything and pulled off the pad and found the wire actually off but it must have been grounding at certain times. Just a very short time to check.

rusnak · 02-19-2007, 06:41 PM

may be a worn ignition switch. Check the windows, defroster, fans, etc. for operation when the horn is not working. Does the engine shut off cleanly when you turn off the ignition, or does it continue to run for a few seconds? These are also symptoms of a worn ignition switch.

wnsgc · 02-20-2007, 03:56 AM

Right now, the car has none of the symptoms you mention. All of the above work fine while the engine is on and the horn doesn't work. And when I turn off the engine, it shuts down immediately. Is there any way to test the ignition switch?

Thanks for your response.

Dutchie · 02-20-2007, 06:06 AM

Quote:

Pull the horn relay and check for corrosion on the pins or socket,

+1

Mine had the same problem and cleaning the relais solved the problem. I think it,s the first relais in the big fuse block in the front of the car but check first.

Mysterytrain · 02-20-2007, 03:09 PM

I also had this problem with my SC. Does your steering wheel have some up down slop? If so you need to replace the bushing with the 928 steel bushing. Do a search on this repair. Its a cheap fix and it will cure both problems. What is happening is that you are losing the ground connection for the horn pad because of the play in the steering wheel. The steel replacement bushing re-establishes the groundthru the steering column.