Horn problems...

rangrayy

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I bought my 1998 Z71 with the horn not working, gave a little wiggle room with price, but figured I could figure it out on my own.

1.I first tried the wire jumper on the fuse panel under the hood and nothing. I even pulled the relay out and put it in our '95 cheyenne and the relay was in working order. Dad pointed out why not switch out horns and see if it is any good. Figured what the heck why not. Well horn still works...

2. Had my dad hit the horn while I was touching the relay and no clicking... put a test light on the relay terminals and on the two closest to the back, not towards the front of the truck, had power to them.

Kinda figured it is behind the steering wheel with the AIR BAG. Do not feel like messing with that and did not realize even after looking at the wiring that there are two horns...

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SO long story short I decided to BYPASS with a 12v inline fused link to a HORN button and then a signal wire out to the horn inside the cab. Well it worked but only out of the PASSENGER's side horn, which sounds awful. I tied into the GREEN wire on the horn right under the hood latch assembly and then plugged it back in.

WHY CAN'T I GET SOUND OUT OF BOTH HORNS?
 

Eveready

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The schematic shows a diode in there. I would check it and the capacitor also shown. A blown diode would definitely prevent voltage from getting to the horn and it could possibly be a factor in your test not working. Also check the quality of the ground. You could have a fine relay and those components could be the issue. Remember the diode is supposed to pass current in only one direction. Check it with a Volt / Ohm meter.
 

rangrayy

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The schematic shows a diode in there. I would check it and the capacitor also shown. A blown diode would definitely prevent voltage from getting to the horn and it could possibly be a factor in your test not working. Also check the quality of the ground. You could have a fine relay and those components could be the issue. Remember the diode is supposed to pass current in only one direction. Check it with a Volt / Ohm meter.

I checked the relay on another truck and it worked fine, along with the horn itself. My problem now is, after I tied into the existing wire on the horn with the bypassed button, only one of the two horns makes a sound. I have yet to check the ground but figured the two horns were grounded in the same spot. Power/Signal is being sent through the one horn and onto the other. I did also check the horn as well with the other truck.
 

east302

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Here are the diagnostics for a 98, maybe it will help. Not sure why both horns don't sound with voltage on circuit 29 unless you have a ground issue between the left horn and splice 128.

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Eveready

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The problem still smells like a ground to me. If one horn ground connect is tied into another one, e.g. two lugs under the same screw, oxidation at that point could very easily give a bad ground to the 2nd horn. I expect the diagnostic steps provided above by East 302 will find the issue but my bet is still on the ground (or a blown diode). Please report when you find it!
 

Steve A

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Might want to check the Multi Function Switch on the steering column, just had a similar situation on my 96 Yukon. Troubleshot it to the MFS, the black wire in Step 11 in the chart above is a ground wire for the horn relay. The circuit wasn't making it all the way to the horn slip ring on the steering wheel.
 

rdimamb

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I have had similar problem with my 98. Once I took off the air bag I looked around. I saw a little plastic insert where the wire is attached to (it has a small spring at the end). This had broken and would not stay in the hole to make a connection. Once I fixed that, the horn worked fine. It is worth looking at it, it could be that simple.
You remove the air bag by twisting a screwdriver in the back of the steering wheel to unlock the retainer. Hope this helps.
 

rangrayy

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The problem still smells like a ground to me. If one horn ground connect is tied into another one, e.g. two lugs under the same screw, oxidation at that point could very easily give a bad ground to the 2nd horn. I expect the diagnostic steps provided above by East 302 will find the issue but my bet is still on the ground (or a blown diode). Please report when you find it!

I thought it was the ground also but I moved the grounds and still only got sound out of one horn. I even made my own harness for the other horn and put to a good ground and got nothing.
 

Urambo Tauro

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Seems to me that if you're getting one horn to sound, and using the same method to power the other horn, then the horn which does not sound must be bad.

Are you going to keep using that button bypass, or pursue fixing the switch side of the horn circuit, too? You'll need to pull that airbag off and possibly the steering wheel as well. A few months ago, mine wasn't triggering the relay due to a dirty slip ring. Just had to be cleaned up a little, and it worked again.
 

rangrayy

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Seems to me that if you're getting one horn to sound, and using the same method to power the other horn, then the horn which does not sound must be bad.

Are you going to keep using that button bypass, or pursue fixing the switch side of the horn circuit, too? You'll need to pull that airbag off and possibly the steering wheel as well. A few months ago, mine wasn't triggering the relay due to a dirty slip ring. Just had to be cleaned up a little, and it worked again.

I originally thought that the horn itself was bad until I plugged it into our 95 chevy and it made a noise. I am very hesitant to mess with the AIRBAG system. How do you go about pulling it off? I know the middle, where you press, is a cover and also houses the airbag. Just unsure and I do not want to just start pulling on stuff. I do know to unhook the battery for at least 15 mins to let the memory reset on the airbag system and to pull the fuse(s). I would like to get rid of the bypassed button and go back to the steering wheel option. I am only bypassing now to pass a state safety inspection for Missouri.
 
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