Non working horn

buddyguy

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#16
There are five elements to the horn system.

The horns, the relay, the BCM, clockspring and the horn switch itself. ALSO, THE 20AMP FUSE (#7)

Normally, applying 12v bat to pin 87 of the horn relay should produce sound regardless. So that would be step one. Try to bypass the relay pin 30 and 87 in PDC. If no sound, suspect bad blown fuse if no juice on pin 30, or suspect bad horns, or bad wiring. If all good, work back from there.


There is no ppl with red stripe in the horn wiring. Here it is to help you trouble shoot.

View attachment 10125
can you suggest a good video showing how to apply voltage to the pin 87 you mentioned to check for sound there. im a rookie. or atleast a video showing similar trouble shooting
 
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#19
Call these a point contact relay, only takes one speck of arc to prevent contact, back in the 50's we were using relays for logic circuits, point contact was considered the most unreliable. Much better choice was a sliding contact relay, self cleaning contacts, most reliable was a mercury wetted contact relay, but out EPA outlawed these, so history.

But is okay to use mercury in CFL's that don't last very long and are throwaway.

Earlier horn contacts in the steering wheel was a slip ring with a brush on it, wouldn't last very long, clock spring gave much better contact and a direct one at that. But guess after 20 years or so, they would get brittle and break.

In today's vehicles, using a lot of point contact relays in that underhood fuse relay box with some even made in China. Some are rated at 50 amperes, really pushing this for a 2 ounce relay. An NEC approved 50 ampere contactor weighs about 6 pounds.

Headlight and ignition switches always used sliding contacts for reliability, now all point contacts, sure can expect a lot of problems.
 
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#20
NickD: Always interesting to read your professional detailed info that most of us know nothing about. I missed those when you were absent for awhile.
 
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#21
Ha, buy silver, supplies are running short and prices will skyrocket. Oxidizes is soft and arcs burn into it very easily, typically either brass or copper is used for the point material.

Contact material they should use is tungsten, super hard, very arc resistant, does have a slightly higher resistance, so contacts should be a bit larger.

Used tungsten for ignition points, good for 10K miles, longer if cleaned. Inductive load, lots of arcing, driving at 50 mph at 10,000 miles, points switched for 2 million times. Full load on silver is only good for about 1,000 operations, so you wonder why you have problems.
 

jd

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#22
I think the slip ring used for the horn back in The Day would make "noisy" contact that's not acceptable for modern electronics. Like airbag modules, steering wheel cruise and radio controls, so on and so fort. Clock Spring is a wiring harness, quiet till it wears out. And, allows all the circuits it takes to make all the new stuff work.
 
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#23
Ha, that was all that was, the horn, now programming for different options, cruise, phone, and radio controls, and in this case, the airbag.

Also have multiplexing, youngest daughter purchased a base model Kia Soul, no cruise. All I needed to do was to purchase a switch for 15 bucks, original wiring harness was short a wire. but to keep it stock, ordered a new one for 40 bucks. Mode controls, cruise, phone, radio, and air bag all went through the same clock spring, but each switch using resistors applied a different voltage through that same clock spring.

A to D converter in the microcontroller provided different codes to either switch those different functions either on or off.
 

buddyguy

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#24
I disconnected electrical connector from one of the two horns and a little while after driving it like that my other hor came on without me hitting the horn and stayed on and only went off after hitting the steering pad horn location a few times
 
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#25
Does that van have the "integrated horn switch/airbag" setup? I have never been able to fix that type of problem. Usually ended up installing a UHB (Universal Horn Button).
A bad "horn pad" may not be your only problem.
 

buddyguy

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#26
Does that van have the "integrated horn switch/airbag" setup? I have never been able to fix that type of problem. Usually ended up installing a UHB (Universal Horn Button).
A bad "horn pad" may not be your only problem.
I may have to do the same looks like
 

jd

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#27
Before Airbags, many cars had two layers of metal under the vinyl horn pad in the center of the wheel. Layers had contact dimples stamped into them and the layers were kept apart by a sheet of foam with holes to let the dimples touch when we pressed on the pad. When the foam failed, the horn would blow on its own and be hard to stop.
I fixed two of those. The first one, removed that layer thing and found a pushbutton switch at Radio Shack that fit under the emblem at the center of the vinyl pad. Second one, I peeled the failed foam out and put thin adhesive backed weatherstrip between the metal layers.
So in both cases, the "horn button" stayed pretty much where it should be. Also, no new wiring.
But, we can't get in there anymore, with that "vinyl horn pad" now part of the airbag.
To install a UHB in this case, the clock spring strand to the airbag/horn pad will have to be disconnected. I hope that operation can be done without setting the bag off, or compromising some other steering-wheel-mounted control feature.
 

buddyguy

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#28
Before Airbags, many cars had two layers of metal under the vinyl horn pad in the center of the wheel. Layers had contact dimples stamped into them and the layers were kept apart by a sheet of foam with holes to let the dimples touch when we pressed on the pad. When the foam failed, the horn would blow on its own and be hard to stop.
I fixed two of those. The first one, removed that layer thing and found a pushbutton switch at Radio Shack that fit under the emblem at the center of the vinyl pad. Second one, I peeled the failed foam out and put thin adhesive backed weatherstrip between the metal layers.
So in both cases, the "horn button" stayed pretty much where it should be. Also, no new wiring.
But, we can't get in there anymore, with that "vinyl horn pad" now part of the airbag.
To install a UHB in this case, the clock spring strand to the airbag/horn pad will have to be disconnected. I hope that operation can be done without setting the bag off, or compromising some other steering-wheel-mounted control feature.
yeah I know what your talking about there because I had that situation with the worn foam piece before and was hoping it might be that simple
 

buddyguy

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#29
Before Airbags, many cars had two layers of metal under the vinyl horn pad in the center of the wheel. Layers had contact dimples stamped into them and the layers were kept apart by a sheet of foam with holes to let the dimples touch when we pressed on the pad. When the foam failed, the horn would blow on its own and be hard to stop.
I fixed two of those. The first one, removed that layer thing and found a pushbutton switch at Radio Shack that fit under the emblem at the center of the vinyl pad. Second one, I peeled the failed foam out and put thin adhesive backed weatherstrip between the metal layers.
So in both cases, the "horn button" stayed pretty much where it should be. Also, no new wiring.
But, we can't get in there anymore, with that "vinyl horn pad" now part of the airbag.
To install a UHB in this case, the clock spring strand to the airbag/horn pad will have to be disconnected. I hope that operation can be done without setting the bag off, or compromising some other steering-wheel-mounted control feature.
as far as setting off air bags are you saying that after installing a uhb with relay and fuse out like I did installing clock spring there would still be risk in setting air bag off? how much money do you think I would be spending in getting a shop to fix this?