I'm hoping someone here can help me out a bit.

So recently my horn stopped working, though I'm not exactly sure when because I use it sparingly. I've taken a look at it and the relay is clicking on and off when I press the horn button, and I believe that the horn is receiving 12V, but I didn't notice a ground from the horn.

Should there be a ground from the horn? If not, I'm assuming that the horn has croaked. Is there a way to fix the horn? Also, I only saw one horn instead of two. If I were to replace this horn and get two, what horn(s) should I get?

Finally, according to the wiring diagram, the horn relay should control the key buzzer, but I don't remember it ever working. Where is the buzzer located?

 

What year? There were different horn circuits throughout the C3 production period.

 

My mistake, it's a 1970

 

Ok

horn(s) is (are) grounded with contact to frame

Yes! They can be rebuilt. And they can be bench tested to determine if its horn or somewhere in the circuit...but you have made progress along those lines.

Year dependent...some had three horns...two horns and one anti-theft horn. Later years had a hi-tone, low-tone and anti-theft.

Year dependent?

As Swampi asked...what year? Those circuits along with # of horns changed over the C3 years

 

Sorry, but I'm not much help for a '70.

From the information I find, '70s came with a single horn. Also the horn relay is in the engine compartment "attached to the inner wheel well". Which wheel well I do not know. Sorry, but I don't know the location of the key in reminder buzzer. In some years it was built into the horn relay but I don't know about '70. In later years it's an electronic unit attached to the fuse box. A very finicky-to-adjust switch in the ignition lock cylinder operates the buzzer and you have to get pretty deep into the column (past the turn signal switch) to access it.

 

Thanks for trying Mike.

I've found the relay and I know that it's switching because I can hear it clicking, but I can't find the key buzzer in the wiring diagrams, so I have no idea where to start in the car.

Also, the AIM shows two horns (though GM may have made a change within the model year) and I see what looks like a mounting hole in the spot on the other side of the car.

Hunt, if I connect a 12V power source to the horn and ground the case, would that be enough to bench test it?

 

When I had a horn issue I found lots of good info using the search option on here. If I remember correctly Willcox had a very good write up on how to test various items to determine the problem. They are sponsors on here and quite possibly he will check in and see your post as he's very helpful

 

 

Not hunt, but yes you can bench test with power to the lug and grounding the case. That's how I did mine.

If you have the factory service manual it should at least describe the location of the key-in warning buzzer. I'm guessing somewhere in the center console as that seemed a very popular place to put things like relays, flashers and other smallish electrical components.

 

My write up was on the 1968-1973 cars has gone awol since we migrated to the new site.. The one below is for 1974-1982 cars and won't help you much other than the logic is the same. I'll see if I can dig out the original 68-73 sheet tomorrow. In the mean time, Jim Shea has a good paper on the 1968-1973 cars on his site.

 

Thanks for the help so far. I just tested my horn with 12V and a separate ground, so it looks like the horn is bad

This is why I think I should have two horns, the green wire that goes to the horn is spliced into two connectors and there is another mount on the other side of the car identical to this horn's mount.



I also took a picture of my horn relay. Any ideas about where my key buzzer is?



D

 

I find conflicting information about both the number of horns and the horn relay/key in buzzer in a '70.

It to does however look more and more like that your key-in buzzer is integral to the horn relay. If so, and despite the fact that it's not in the passenger compartment it is both very loud and obnoxious in tone--you could easily hear it both inside and outside the car... I seem to remember the same in my '71 Chevelle and given the large gauge wires in your photo it sure seems the same as I remember it having a problem that took out nearly all of the electrical system.

 

So the horn relay is also the key buzzer?
I thought that it acted as a relay for both the buzzer and the horn

 

The key buzzer on my '75 is a white rectangular plastic thing. I have a picture of it somewhere if you think it will help.

 

I just check my 1970-72 NCRS Ops manual. It states that 1968-1970 were equipped with a hi-note horn and a low-note horn. 1971 and 1972s had a single horn. The part numbers are GM# 9000245 on the passenger side (low note) and 9000246 for the driver's side (high note). Horns have date codes that are stamped or embossed. The codes are A = January, etc and I is not used. This should help you track down which one you have and which one you are looking for.

I used The Horn Works to have my horns rebuilt. Guy's name is Gary and was good to work with.

Your hunch that your 1970 had two horns is on target!

 

Yes! The 1970 AIM, page 227 shows the horn relay mounting (driver's side fender well) and describes it as GM# 1115889, Relay & Buzzer ASM - horn.

 

Mine is also a 1970 and it has two horns, high and low. There should be another mounting hole on the passenger side opposit the one in your picture. I'm at work right now but I have pictures I can post shortly.

Chad

 

Ditto

I've also looked for a key buzzer in my 70 and never found one. The horn relay is just that, a relay and is not also a buzzer. I also have a set of Dr Rebuilds wiring diagrams snd don't see a key buzzer, but I could have missed it as there is Ã* lot of info on the diagrams.

 

The horn relay is the key warning buzzer on your 1970.

I can't seem to locate my easy schematic but this is from Jim Shea's page...

HORN OPERATION DIAGNOSIS - ALL C3 CORVETTES 1969 THROUGH 1982

There are three basic areas that can cause your horns to not operate: 1) the horns themselves;
2) the horn relay/key buzzer; 3) the horn circuit in the steering column and steering wheel parts.

1) Horns - There are two horns on most Corvettes. There is a dark green 14 gage wire connected to them from the horn relay. Disconnect this wire from the horns and connect a 12v source to the horns; they should operate. If they don’t, the horns need to be repaired or replaced.

2) Horn Relay/Key Buzzer – Early Corvettes have the horn relay mounted underhood, on the driver’s inner fender, near the brake master cylinder. Later models have the horn relay mounted inside the car, under the dash on the instrument panel wiring harness coming out of the fuse panel.
Remove the relay from its mounting and identify the #2 and #3 terminals. Connect a jumper from the terminal marked #2 to ground. Slide a probe into the wiring harness connector to make contact if the terminals are the slip-on type. If the horns operate, check the #2 terminal wire and horn switch for defects. If the horns do not operate, leave the #2 terminal connected to ground, and connect a voltmeter from the #3 terminal to ground. If a reading is obtained, check the horn wiring and horns for defects. If no reading is obtained, replace the horn relay/buzzer.


3) Steering Column Wiring - The steering column has a flat (harmonica) wiring connecter that connects it to the vehicle instrument panel electrical harness. The last wire in the steering column connector is a black one. Next to it is a pink wire. The next wire (the third one) is another black wire. There should be continuity from that third black wire up to the spring loaded eyelet plunger sticking up at the horn button upper contact on the steering wheel. If not, the problem is within the steering column itself.

4) Steering Column Continuity - When you press the horn button there should be continuity from the third wire all the way to the lower end of the steering column steering shaft and across the flexible coupling to the flange that mounts to the steering gear input shaft. If not, the problem is somewhere within the steering column, flexible coupling, or steering wheel horn parts themselves.



-Willcox

 

Thanks Chad and Hunt!

I was pretty sure that I was missing one horn, but I wasn't sure which one. And I see the mounting hole for the other side. I was digging a little deeper for the key buzzer and found this, which might help me test the buzzer.



Ice, I think that Hunt and Mike were right about he buzzer. That connection at the top might create the buzzer (when the key/door circuit is complete, the coil is repeatedly powered and unpowered). Now I'm wondering if it is that part that makes the buzzer (a relay clicking on and off at a high frequency) or if it completes the circuit to the horn repeatedly as well to create the noise.

Anyways, I think I might have a bad key warning buzzer switch in my steering column that I need to take a look at.