Horn honks when hooking up to battery

[MY1978]

So, I apparently need high caliber brains to fix this.  I went to put the steering wheel back on, after trying to clock it, and I noticed that the steering wheel was on upside down, but because the wheels were turned slightly out.  So I started the truck, straightened them all without incident except then the horn would not blow.  So I pulled the steering wheel off, removed the locking plate and made sure the cancelling cam was seated correctly.  Put everything back together and when I went to hook the battery back up, the horn blew.  So AGAIN broke it down to the cancelling cam, AGAIN the horn blew.  So I decided to try just putting the cancelling cam and locking plate back in place - and the horn blows.  WTH!!!  it wasn't doing that when I started it to straighten the wheels.  Any thoughts or ideas.  Prior to this the horn was fine.  I was watching some videos and I will check the horn spring and fuse today.  I also have all the parts ready to order in my cart from where I have ordered parts from.

1978 Chevrolet, C10, 350,

[bd]

Either the horn relay control circuit is grounded, or the relay is faulty.  Does the horn blow with the lock plate and the cancelling cam removed?

[MY1978]

Was late yesterday when I threw my hands up and said I am done.  I am going to try that today.  I have some other things to do around the yard, then will go back to that.

Thanks

[bd]

The resolution should be simple, and may be obvious once you direct your attention toward it in this new day.  Once you remove the c-cam, pay particular attention to the copper brush that rides up against the cam.  With the battery connected, depress the brush a few times using your finger to see what happens.

[MY1978]

Okay, it has been a few weeks since you replied and I do appreciate that.  Stuff just got busier, but back at it. 

I have not tried your suggestion yet about depressing what you call the "Brush".  I assume you are speaking of the button that makes contact with the c-cam.  I will try that.

But, I did notice that the locking plate is bent.  How you ask?  Because the tool to compress the plate was a wide one and the legs rested on the outer edge of the plate and bent the plate.  Probably the off, on, off, on, off, on caused it to get bent.  So I found, and ordered a replacement locking plate - came with new plastic cover and clip.  I also ordered a compression place/steering wheel puller kit, from our friends at Amazon, with a narrower compression plate tool.  I thought HA!!!!  problem is going to be solved.  I put the locking plate on, placed the clip in position, released the plate,hooked up the horn and BLAHHHHHHHHHH.   Well, dang!!!!! Disconnected the battery AGAIN. 

After I try your suggestion, if it doesn't work, I am going to order/buy a new canceling cam in case that somehow is now the problem.  Also ordering a new horn relay just in case although it was tested and seems okay.

This is getting REALLY frustrating.

[VileZambonie]

The canceling cam has the contact ring and they wear out. It's very common to have the horn randomly sound as you rotate the wheel when they're bad. Almost any auto parts store stocks them.

Dorman 83230 & 83232 for tilt column.

The contact is trim to length if you even need it.

[MY1978]

Thanks.  This is a replacement c-cam because the original was broken a few years ago.  Before I took the steering wheel off to try and clock it since it was slightly off (which I wish I would have left the dang thing alone), it was working fine.  Like I said, I will get a new c-cam and relay to cover all the bases.

[JohnnyPopper]

Looking to the outcome. I disco'd my horn a couple years ago due to random honkiness. Sure do miss it when certain Valedictorians are on the road...

[MY1978]

Looking to the outcome. I disco'd my horn a couple years ago due to random honkiness. Sure do miss it when certain Valedictorians are on the road...

[MY1978]

With the battery connected, depress the brush a few times using your finger to see what happens.

Sooooooo, we are hoping the horn does, or does not, honk.  Or will I honk because I will be shocked.   

[bd]

The brush rides against the cancelling cam brass ring.  The idea was whether the brush broke loose from the switch so that the back side (the wire terminal side) is grounding.  Try this: With everything above the turn signal switch removed, connect the battery.  If the horn honks the problem is physically limited to somewhere between the turn signal switch and the horn relay (e.g., the turn signal switch black horn wire is chafed to ground somewhere inside the column, the relay is faulty, etc).  If the horn does not honk, with the battery still connected, assemble the upper column one-piece-at-a-time to determine when the symptom appears.  Get the idea?  The cause of the problem is simple, but easy to overlook, especially if assumptions are made. 

[MY1978]

OK bd, I took every thing down to turn signal, connected the battery and depressed the button about 10 times.  Nothing.
I have replaced the relay, just to be on the safe side.  I have broken this down and reassembled multiple times and it is when the locking plate is in place that the horn blows.

Now, I also ordered a new cancelling cam.  It has a protector? on the top of it - my other one did not and I do not think the original had it.  I have not removed it.  Before I go further, please look at these pictures.  The new c-cam pin is much longer than the old one and when depressed is still sticking up a little. 

Question now, before I start reassembling is - should I cut the pin down to the same length as the old one?

Thanks for all your help.

[bd]

• The "protector" on the top side of the c-cam is an insulator that prevents unwanted grounding of the three locking tabs that protrude through the plastic cam from the contact ring below.  Leave the insulator in place.
  
  
  
  
• The c-cam towers  ^^^^^  should have identical heights.  Rather than cutting the new aluminum contact pin to length, transfer the pin and retainer from the old c-cam.  Don't forget to install the compression spring below the pin.
  
  
• "...it is when the locking plate is in place that the horn blows."  Whether or not you stated this before, it is new information to me.  Forgive me, but since I'm not peering over your shoulder as you work, did you reinstall the stiff compression spring below the c-cam?  (Although the following images are from a tilt column, the concepts are the same as a standard column).
  
  
  
  I don't know whether it is even possible, but are you installing the locking plate upside down?  This is how it should appear installed...
  
  
  
  
• As you reinstall and assemble parts, take your time and watch very carefully for any place where the c-cam brass contact ring might touch other metal parts that are grounded.  Make sure the turn signal switch cancelling springs are intact, in place, and not distorted (see below and very bottom images).  Similarly, check the flat springs of the turn signal detent and four-way flasher switch.  Longshot: Imagine yourself miniaturized inside the assembled mechanism, looking around.  Now, try to conceptualize where you might accidentally come into contact with an adjacent metallic ground.  (No jeering.  For some people, this approach works surprisingly well.)
  
  
  
  
• Assemble to just short of installing the locking plate.  Press the c-cam downward against spring pressure to hear whether the horn honks.
  
  
  
  
• Refering to the last image for clarity, pressing the "contact ring brush" downward was to determine whether its backplate had dislodged, allowing the horn wire to touch ground underneath the switch, where unseen.

[MY1978]

WOW!!!  Thanks so much. 

1.  I kinda thought that the "protector" was some type of insulator.  Funny that it wasn't on the original or the 1st replacement.  Maybe that is what was causing the problem since the one I was replacing did not have the insulator ring.
2.  I didn't even think about moving the contact pin.  Wow!!  feeling stupid about now.     Next crazy question is should I use the old spring or the new spring.
3.  Yes, the compression spring is in place.
4.  Yes, locking place is being installed correctly.  Trust me, out of frustration I tried to see if it could be installed the other way.  It cannot! 
5.  Will try pressing the c-cam.  That spring is so strong, I don't want to break the c-cam.

Thank you so much for the pictures and taking the time to explain things.  I will update at a later date.

[bd]

Responses embedded...

WOW!!!  Thanks so much.  You're welcome!

1.  I kinda thought that the "protector" was some type of insulator.  Funny that it wasn't on the original or the 1st replacement.  Maybe that is what was causing the problem since the one I was replacing did not have the insulator ring.  The insulator ring was added as insurance at some later point in production, though I never encountered a situation where it was necessary.

2.  I didn't even think about moving the contact pin.  Wow!!  feeling stupid about now.     Next crazy question is should I use the old spring or the new spring.  Personal preference.

3.  Yes, the compression spring is in place.

4.  Yes, locking plate is being installed correctly.  Trust me, out of frustration I tried to see if it could be installed the other way.  It cannot!  Thanks.  I really didn't suppose it would.  Seems to me I ran the same experiment some 40+ years ago - lol.

5.  Will try pressing the c-cam.  That spring is so strong, I don't want to break the c-cam.  You won't be able to depress the c-cam more than about 1 mm by hand w/o imparting damage.  The better idea is to look at it and all the connecting parts as you fit things together slowly.  Watch for the changes in the proximity of pieces as the plate is compressed.  At what stage of plate compression does the horn complain?  Why?  What made contact?

Thank you so much for the pictures and taking the time to explain things.  I will update at a later date.  Look forward to it.