Author Topic: Fixing a dead horn - a newb's first attempts at electrical work  (Read 5715 times)

Offline jforest1

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Fixing a dead horn - a newb's first attempts at electrical work
« on: December 15, 2010 - 10:26:43 PM »
So I've been playing around with the idea of fixing a non-working horn for a while, and figured it would be a good intro into troubleshooting electrical issues with the car, etc.

So my first stab has proved...educational.  :)

I started out with a little help from my older brother...intro to electricity, DC current, etc.  Then I went on the interweb and read some more.

Then I dove into the maintenance manual and stared blankly at the wiring diagrams.  Then I sighed, closed the manual, and went to the car.

First things first, grabbed some speaker wired and jumpered directly from negative to low horn lead...nothing. 

Sigh...

Wondering if its bad or if I just silently blew out the otherwise-working horn by overloading it (the fuses are there for a reason, right?).  ****, if I did, I might as well blow them both out.  You gotta press the big red button every now and then...

Touched negative to high horn lead, BEEEEPPP!

Nice.  So I got SOMETHING, and I know I (probably) didn't blow out the low horn.

Problem #1 is no low horn.  We'll defer on this til later.  Let's just get something working.

2 hours pass during which I realize my speaker wire is probably not the BEST jumper wire (so I bought a voltage meter to act as a test light/jumper wire because I have no idea how to use a voltage meter), the horn relay is probably good because my key buzzer works, but somehow jumpering from the fuze directly to the horn results in silence. 

After questioning my newfound understanding of electricity and DC current, I figure there must be an open circuit between the horn and the bulkhead disconnect. 



Problem #2 is some shmoe cut the cable clean and then taped it back up before and plopping some shielding on it.  And no, it didn't just get pulled out of the coupler there, because it's 2" too short to even go in it (I tried).  Patched it and connected battery to horn where the horn relay goes...BEEEEEP! 

Put the horn relay back in, test the horn at the steering wheel.  Nothing!  Blast.  Removing the center pad from the steering wheel took a lot of courage...there's no obvious way to do it until I inspected it very thoroughly from a 60 degree angle through the crack on the side when the sun was directly above me...  Of course knowing is half the battle and I simply forcedly removed it and nothing broke. 

And voila:



Now I look back at the maintenance manual wiring diagrams and like that, they started making sense.  Of course now I don't need them anymore because I already know what the circuit is supposed to look like but will be handy when I try to troubleshoot my console gear shifter light on my slapstick recently going out...

Now by my reading, there is supposed to be a wire actually connected to that lead that is currently bare, and if that's the case, it will complete the circuit and I'll have a working horn.

Now for questions:
1.  i'm pretty sure it's the case, but just want a little confirmation before I attempt taking apart the steering column:  is there supposed to be a wire there?

2.  assuming I get it all working, I still sound like a volkswagon beetle when I honk.  i read somewhere that you can test a bad horn to see if it's "tuned" properly with a voltage meter?  can this be the source of my non-working low horn?  if not, where can I get a new one ('73 cuda)?  haven't really noticed these on the usual sites in my browsing.
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system




Offline Bullitt-

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #1 on: December 16, 2010 - 12:46:39 AM »
I see in the last picture the ground wire is not connected to the horn button, take the 3 nuts off & the steering wheel will come off hopefully revealing the ground wire.
New original type horns are not available, either seek out good used or buy generic replacements at any auto parts store.  I've read here somewhere that dead horns have been resurrected, worth a shot.
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline dutch

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #2 on: December 16, 2010 - 02:54:54 AM »
both horns on my car were dead.  I drilled out the rivets and cleaned up the inside. Cut thread where the rivets used to be and bolt it back together. Cut a new paper gasket ( doesn`t really matter what gauge ). Works like new and sounds like an army of beetles.  Costs: a sheet of paper and a couple small bolts.





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Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #3 on: December 16, 2010 - 12:30:15 PM »
Thanks for the tips.  Will let you know how it goes!

JF
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #4 on: December 19, 2010 - 01:54:50 PM »
dutch,

Thanks for the insight into the horn.  I drilled out the low horn that wasn't working, and before assembling it tested it to confirm it works.  It does.  Now I just have to run out and get some bolts/nuts for reassembly.  Outlook good.

Bullitt-,

However, on the other end of the circuit, there's no black wire under steering wheel (though I do see it entering the column with the rest of them from the harness by the fuse box), and it looks like I need tool C-3428B to remove the can assembly from the bearing housing.  Any ideas for how to purchase a tool that will do this job?

My plan is to backtrack down the column to find where the black wire disappeared.

JF

p.s.  I supposed while I'm in there, I'll replace the key ignition in the lock housing so my doors will match the ignition key...
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline dutch

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #5 on: December 19, 2010 - 03:52:43 PM »
I cut thread in the drilled holes. Didn`t use any nuts. I also had some problems with one of them. After assembly it didn`t work.. turned out it needed some fiddling with the adjustment screw that`s in the housing.
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Offline Bullitt-

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #6 on: December 19, 2010 - 04:40:20 PM »
I've read several suggestions that to remove the can any steering wheel puller will work but you need extra-long bolts to accommodate the depth of the can. I have a large PDF file that covers steering column assembly that I can email you a link to download. You will need to email me 1st, use the email icon under my profile to the left.
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline Bullitt-

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #7 on: December 20, 2010 - 12:32:30 AM »
You should have an email from DropSend with a link to download...let me know if there are any problems
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #8 on: December 20, 2010 - 12:07:32 PM »
Got it.  Thanks Bullit-!

Getting to that starting key cylinder is a bit more involved than I thought!

JF
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #9 on: December 27, 2010 - 03:06:15 PM »
dutch,

I fixed the low horn by replacing the paper gaskets and tuning it properly (for anybody else reading the tuning screw adjusts the height of the metal strip on the inside that opens/closes the circuit.  When it is down, the circuit opens, turning off the electromagnet at the base that draws the cylinder/plate down.  This allows the cylinder/plate to rebound, allowing the metal strip to move up and close the circuit, which then turns on the electromagnet again.  Wash rinse repeat.  Each time the plate oscillates, it makes a waffle sound, and when it happens quickly enough, a horn (or army of beetles).  So the tuning screw, if not at the proper setting range, will either keep the circuit fully open or closed, which will prevent the oscillation of the plate.  You'll know this is the case when absolutely nothing happens or just an initial pop sound (hard to differentiate from battery spark) when hooked up to the battery directly.  When in the proper range, you can fine tune the tuning screw to make the horn slightly higher or lower.

Thanks for the tips and hope this helps others! 

Bullit-,

I've now got can off (confirm:  I did have to get some extra long bolts (5.5" IIRC) from Home Depot to get the steering wheel puller to work).  Also, for anybody else reading this post, don't be surprised if it takes some extra effort to pull that can out.  It was in there TIGHT.

No black wire under the can.  I'll be diving deeper now; as I need to replace the key cylinder anyway, this is planned.  Now if I can just find the time...


JF
« Last Edit: December 27, 2010 - 03:12:34 PM by jforest1 »
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline plumbeeper

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #10 on: December 27, 2010 - 10:20:20 PM »
The bottom of your crush can should look like this one. It should have a copper contact ring on it with a lead wire attached to it. The other end of that wire plugs into your switch. Without that contact, you won't be able to blow the horn. Please post a pic of your crush can and we'll help you figure it out. I can repair it for you if necessary.

Dave

Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #11 on: December 28, 2010 - 12:44:55 AM »
One last thing on the horn before I continue on the electrical side.  I think someone said you can't find reproductions of the original horns, but here they are on year one:

http://www.yearone.com/serverfiles/fbshopmain2.asp?subsection=1&ssid=112BI&trk=12&searchid=4920890

My update:  I dove in tonight and found !!!3 more problems!!! with the electrical hookup.  Will post photos when I get them off my camera.  I'm beginning to think that someone deliberately sabotaged the horns!

JF
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline Bullitt-

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #12 on: December 28, 2010 - 08:04:05 AM »
One last thing on the horn before I continue on the electrical side.  I think someone said you can't find reproductions of the original horns, but here they are on year one:

http://www.yearone.com/serverfiles/fbshopmain2.asp?subsection=1&ssid=112BI&trk=12&searchid=4920890


Look again.. "Replacement"  These are not reproductions, although they do look a little like OEs.
There should be more than enough in the salvage yards & generic replacements can be had for way less than $70 ea. 


Y1 piece looks suspiciously like this $16 Autozone one
« Last Edit: December 28, 2010 - 08:09:39 AM by Bullitt- »
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline jforest1

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #13 on: December 28, 2010 - 09:53:58 AM »
Bullitt-,

I stand corrected.  Looking closer at the reproductions, seems they are all for Roadrunners.  Right you are!


So with y'alls guidance (MANY THANKS), I was able to get the right tools to remove the crush can, only to find no black wire underneath.  No worries, I needed to replace the starting key cylinder anyway.  So I started unscrewing all the turn signal assembly to remove the bearing housing, and low and behold my black horn switch wire:



It was a clean cut, as if someone snipped it, I stripped one side to begin jumpering to see if the wiring up until that point was good (hey, no assumptions anymore after this electrical debaucle).  After getting nothing for a while, I gave up for the time so I could think about it while getting the new key cylinder in.

Back to the bearing housing.  No idea how to get it off, seemed very stiff and no apparent way to remove it.

So I do what I always do when I'm frustrated at something else, I took a deep breath and forced it.  It wiggled free!  Actually, not sure if this was a good thing or not.  It seemed to take the whole steering shaft with it (yes, I removed the snap ring in front of the bearing), and I wasn't sure if this was in fact removing the shaft from the steering gear at the base of the steering column (in the engine compartment)...the up side was that now I could get to the lock housing and replace the key cylinder.

Replacing the key cylinder was as easy as removing the two screws and the plate underneath them, then pressing the cylinder release button and pulling it out.  Greased the new one, put it in, voila!

Now, to get the bearing housing back in, made sure it was aligned and forced it back into position (with some wiggling).  I ASSUMED that because it got back in place that whatever I pulled out before is also back into position, figuring I'd find out when I get the crush can back on and test out the steering...  If anybody knows what this was or if I could have done something to avoid pulling out the shaft, please share.

So back to my wiring.   I quickly reviewed my assumptions:
1.  Key buzzer is working for the horn relay. 
2.  Jumpering from 1 to 3 on the horn relay socket sounds the horns (both of them, yay!). 

After a bunch of tinkering with no success, I resorted to the maintenance manual flow chart.  In jumpering from 1 to 2, then from the stripped black wire in the bearing housing above, back to 3, the horns sounded.

I believe this to mean that the horn relay is bad because I completed the circuit just fine without it.  Is this correct?

I went ahead and ordered a replacement horn relay.

Now I butt-joined the two ends of the black wire, put the turn signal assembly back on, and retested, this time jumpering 1 to 2, then the retractable copper lead that touches the can assembly ring back to 3.  Horns go off.

Okay, So I've got a working circuit, minus the horn relay, up until the crush can.  But now I've realized another problem I didn't notice before:



The ring that retractable copper lead touches is broken off (and of course no wire).  Okay, so I guess I have to get a soldering tool to repair it, but at this point, I believe I can create a wire that goes from this ring to the lead on the center pad of the steering wheel and get it all working.  I went ahead and brushed the rust off to get it clean (shown above after the brushing).

One other question I had is that the copper ring on the crush can that the retractable copper lead touches is loose and rotates on the crush can.  It's supposed to be tight against the crush can and rotate as you steer, right?  If so, what do you guys recommend for getting it stationary again?  Superglue?

JF

'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system

Offline plumbeeper

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Re: Fixing a dead horn - a newb's first attempts at electrical work
« Reply #14 on: December 28, 2010 - 12:45:40 PM »
The ring that retractable copper lead touches is broken off (and of course no wire).  Okay, so I guess I have to get a soldering tool to repair it, but at this point, I believe I can create a wire that goes from this ring to the lead on the center pad of the steering wheel and get it all working.  I went ahead and brushed the rust off to get it clean (shown above after the brushing).

One other question I had is that the copper ring on the crush can that the retractable copper lead touches is loose and rotates on the crush can.  It's supposed to be tight against the crush can and rotate as you steer, right?  If so, what do you guys recommend for getting it stationary again?  Superglue?

JF


Well, I can see from your picture that you have a few problems here that can be corrected. First, your copper ring needs to be flat and smooth. Judging by the pry marks on it and the canister, someone has tried to remove it for some reason. If it is not flat, your horn will be inconsistant depending on what position your steering wheel is turned when you blow the horn.

 The copper ring is held in place by the spring clip. It will have to be pressed on tighter to hold the copper ring tight. This spring clip also serves as your turn signal cancelling arm. It must be in the correct position as well. The copper ring must be insulated from grounding against the canister.

 The wire can be soldered onto the copper ring and put a spade terminal on the other end to connect to your horn. Make the wire plenty long enough to reach the horn switch without being too tight. You can stuff the excess wire down inside the canister after you install the steering wheel.

 The pry marks on the outer edge of the canister may nned to be straightened a little to prevent it from rubbing the column when you reattach it.

 Let me know if you need any help with getting it back into shape.

Dave