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Discussion Starter #1
So I bought a 96 RMLS. I noticed the horn fuse was removed. I replaced it. And when I pressed the horn button, the horn would not stop. So, I went through the trouble shooting flow chart for "Horns 'on' at all times".

1. Remove horn relay are horns on? NO
2. Connect test light from convenience center terminal 87 to terminal C9 is test light on? YES
3. Check for short in circuit 28 (did no do that) If okay, repair or replace steering wheel horn contact plate.

So, I DID try 3 other horn relays and that did not help.
Then I took OFF the SIR and horn assembly from the steering wheel and horn did not come on. So that eliminates "short in circuit 28".

That leaves the horn button or contact plate. right?

I got a whole other horn, SIR assembly from a junk yard and that did not solve the problem. I played around, I inserted the spring loaded hot wire, and no sound. Then I ground the ground wire against the wheel and BLAAAHH! Horn on!

What are the chances that ANOTHER horn button/contact plate is bad? Is this common?

Remember, my horn did not sound UNTIL I put in the fuse, and THEN pressed the horn button. Do the plastic covers shrink in the sun enough to where they force the horn button to contact the plate or something like that?
 

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Did the horn stop when you removed the wire, on the spring loaded connector, from the wheel? If so, it is a 99 pct. chance that it is the horn button.

The horn buttons are notorious for the problem you are experiencing. All 94-96 RM sedans and wagons have the same airbag. The chance of one from the local junk yard being bad is about 50/50. Some people have replaced the switches with momentary contact ones from Radio Shack. There is a thread or two on mounting them, but I have not seen them for a while.
 

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Discussion Starter #3
Yes the horn will stop if I remove either the hot wire with the spring or the ground wire from the steering wheel.

So, since it is a common problem, I will try another unit from the junk yard this week. I am experiencing "common problems" for the first time even after my late father and I have each had several of these Roadmasters only within the last month with two recent purchases.
 

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I hope this stuff don't turn you to MOPAR. cwm2

Hey you and your father seem to have had "unreasonably" good luck skirting some common issues. Probably be catching up as these incredibly high quality engineered cars continue to age.

To make you feel better I had a problem with a real nice Riv 30 years back the horn started to go on for no reason. Always at 1am. Only when with a cold snap. It happened a couple times and the neighbors joked about it. Disassembling the horn there was two flimsy copper plates separated by 1/16" foam pad punched full of holes. The vinyl cover shrinking at night was squeezing the horn on. Hi tech.

I bought a brand new assembly ($90 was still some money back then) and all better. Less than one later and EXACTLY the same thing. That time the neighbor's phonecall in the middle of the night was P-I-S-S-E-D!

Even the NOS was dry-rotting on the shelf.

Almost forgot my point. No matter what I did to the wheel the horn would not go off, but disconnect-reconnect the battery and it stopped. Hit the horn again and it would stay on again. Something about once arced on, it staying connected.

Maybe part of your symptoms. Good luck.
 

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I have a Caprice but think the RM uses the same type AB and Wheel setup. Not sure what swapping the AB (SIR) would do since the contacts for the Horn Circuit are on the wheel. Here is a pic of what I found when I replaced my wheel.






I do know that if you tighten the AB module (2 Torx Screws) too tightly to the wheel it will cause the Horn to stay on constantly.

The horn works if you just touch the Red Spring loaded wire to Ground. What happens if you do this and bypass the horn buttons on the wheel? If it works as it should then you most likely have bad buttons on the wheel. Maybe meter across the Black and red wires of the horn button circuit. If they appear to be shorted, then I think you found your problem.
 

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Discussion Starter #6
The Buick does not look like that. Once you take the horn/SIR off all you are left with is the steering wheel and the one yellow wire that connects the SIR to the steering column.

When I plug in ONLY the red wire with the spring, there is no sound. Once I ground the black wire to the wheel the horn goes off. This is when the SIR/horn unit is not even screwed on, so the tightness of the screws is not the issue. Good idea though, I will check for continuity between the hot and ground wire on the SIR/horn units today.
 

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The Buick does not look like that. Once you take the horn/SIR off all you are left with is the steering wheel and the one yellow wire that connects the SIR to the steering column.

When I plug in ONLY the red wire with the spring, there is no sound. Once I ground the black wire to the wheel the horn goes off. This is when the SIR/horn unit is not even screwed on, so the tightness of the screws is not the issue. Good idea though, I will check for continuity between the hot and ground wire on the SIR/horn units today.
BTW - Love the thread title....




It does sound like the Horn Circuit is working like it should. Here is a pic of the Horn Circuit shown with the Black Wire (Ground) Mounted to the Hub and the Red Wire (Coverd in Black Heat Shrink coming thru the hub) from the Spring Connector going to the Horn Button of the grant wheel.

Press the button, short the circuit and the horn sounds. Pretty basic circuit for the most part. Maybe it will help you visualize this and you can then take a closer look at the Stock horn Button and determine what in that part of the circuit is not working. Just did this to test the Horn Functionality before buttoning up the new wheel.


 

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Discussion Starter #8
I just checked both SIR/horn pods for continuity between the red and black leads and the circuit is closed on both of them. So, now I will take my meter to the junk yard and find a unit that has an open circuit. Well now at least I know for sure what my problem is.
 

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Sounds like you found the problem. Taking a Meter with you to test another would be a good idea then. But.....is it possible at all to take apart the Stock unit and try to rebuild/fix it? What causes it to fail?

I've had some good success taking apart certain items that you normally would just trash....cause I'm a cheap SOB, but also like to see what makes something work and can it be fixed.
 

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Discussion Starter #10
Now meso sleepy....

FIXED. I took my meter to the junk yard and it was the FORTH one that had an open circuit. I brought it home and just finished installing it. What's more, I do not have to hunt or press so hard to activate the horns. It works great!

So now I know of another common problem. As far as taking one apart. It looks like it is not very easy without screwing up the plastic cover. But I will save my old one for future study.
 
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