Intermittent horn issues

[91Bear]

Okay, I've got horn issues with my 1969 F-100. My grandpa gave up and installed an auxiliary button on the side of the column. I took it off and replaced the turn signal switch. I also replaced the solenoid. I added a second horn, just because I liked the sound of two vs. one. It wasn't working at all until I sanded some paint off the horns to ground them. It was working great and now the intermittent problem has returned. I can hear it click and the horns make a growling sound and sometimes honk. Most of the time they don't.

I was watching this video and he uses a long wire with a fuse to help diagnose the problem. (https://www.youtube.com/watch?v=QCybUPR4iog)
Where do you get wire like this and what gauge?
I have tested the horns straight to the battery and they work fine. The problem is somewhere in the switch/wiring but I don't know much about electricity.

Can anyone give me some guidance?

[Fraser]

I had a similar issue with my '77, replacing the rag joint solved it. The flexible brass jumper in it was broken. It will still ground without it, the horn finds an alternate ground through the bearings, but it's not as solid.
Or at least that's my theory, some say I'm wrong, but try grounding around the rag joint and see.

[390xlt]

When I replaced my rag joint, I made a short wire with a ring terminal on both ends to take the rag joint out of the grounding equation entirely. Has worked well so far

[91Bear]

You just attach the rings to the bolts on the rag joint?

[Fraser]

Yes, basically you are jumping around the rubber part. Leave enough slack to flex, but not enough to snag on anything.
Not all rag joints have a flex terminal built in, my '77 did. Still, it's worth a try, and won't cost a lot to add.

[390xlt]

Yep, that's exactly it. And like Fraser said, make sure it's not too long

[91Bear]

OK. Did that. The rag joint has a wire jumper. The horn honks when I go straight to the battery. I guess it's either in the wiring or in the horn button itself. Maybe a brush is not making a good connection.

[390xlt]

It's almost certainly an issue with a bad ground somewhere. My guess -- like yours -- is that it's probably in the steering wheel and/or horn button. I'd take it apart and check that everything is working as it should on that end. Might as well double check your work on the turn signal switch while you're in there. If you still can't identify the problem, it's time to start tracing wires

[91Bear]

The main thing I dread is that when I passed the wires down the steering column that I rubbed off some of the insulation on one of the wires, although I taped them up when I was threading them through. It's just a colossal PITA that I would hate to have to do it again.

[Fraser]

Agree it's likely in the column, but if you want to verify the relay and underhood wiring first, this is how I would proceed. I am assuming everything is stock, non stock is a different ball game. First, make sure all the contacts on the relay are clean. The relay has a hot terminal, a wire to the horn, and a trigger. I don't have a schematic, however with a test light you can find which is hot. The wire to the horn is the same colour as the wire at the horn, the other is the wire to the switch, or trigger, it is probably a smaller gauge. If you ground it you should hear a healthy click, and the horn should sound. if not, the problem is in the relay or wiring (or horn, but you say that's been tested). Next, jump the other 2 wires, if the horn sounds, the relay is bad, or the switch. Next, attach a test light from the battery to the relays trigger wire (relay unplugged) and see if it lights when you press the horn button. Let us know how these tests pan out, and we'll go from there.

Edit; Actually, try that 3rd test first, it will verify the column head, which seems to be where everyone is leaning.

[zgerbic]

Sounds like a ground problem or a bad relay based on the symptoms.

It is probably best to work from the horn back to the steering wheel.
1. Figure out which wire on the horn relay is which. Wire 1 goes toward the firewall and is the horn ground wire. Wire 6 goes to the horns. Wire 33 goes to the battery at the starter solenoid post.

2. Wire 6 goes from the relay to the horns. Touch a wire from the battery to the wire 6. The horns should both sound very loudly. If not touch the battery wire to the actual terminal on each horn and they should both honk loudly. If not they are not properly grounded or are bad.

3. Attach a wire to a good ground point on the engine and touch the other end to Wire 1 connection on the relay. If you cannot get to the wire 1 connector, try placing a the test wire in the connector and plug it into the relay, then touch the other end of the test wire to the alternator. You should hear a very clear click of the relay and the horns should sound loud. If the horn does not make a solid click and sound the horns, either the relay is bad or the wire 33 is not supplying enough power to the relay. If the horns and relay sound loudly then the problem is further upstream toward the horn switch.

4. Have someone stand next to the horn relay and try honking the horn with the horn ring on the steering wheel. Does the relay close with a good snap? If so the horns should sound. If not there is a grounding problem between the connector on the steering column for the turn signal wiring and the horn button/ring behind the steering wheel. In this case something probably mechanical is not right with grounding.

5. I would make sure the engine is well grounded to the firewall by the flex strap that goes from the manifold to the firewall. I would next hook a wire to a ground point under the dash or on the firewall and hold it against the steering column at a bare metal spot. Try honking the horn. If it honks now, there is bad grounding between the firewall and the steering column. If it still does not honk clearly I would unplug the connector for the turn signal wiring and find the blue with yellow strip wire connection in the corner of the six pin connector (leading away from the steering column. This wire should be the same color as the wire going into the relay that makes it honk. Connect a ground wire to a ground point under the dash. If you touch the ground wire to the connector pin and the horn honks, the problem is in the mechanical switch ring or wiper contact under the steering wheel. That is all that is left in the circuit. I would take off the steering wheel and look for a bad wire or bad ground for the horn contact ring, or the wiper does not make good connection.

There is not much in the horn circuit. There are the horns which connect to the relay, the wire to the turn signal connector and the horn ring button assembly, which provides a ground to the relay. A good sounding horn that has a weak sound when the horn button is pushed is usually burned contacts in the relay. If the horn relay barely clicks or buzzes it is usually a bad ground from the horn switch to the relay.

As some people have pointed out, because of the age of these trucks, grounding problems can cause all sorts of strange problems.

The 1968horncircuit.jpg diagram shows the horn circuitry and color code for the wires. The 1967 master wiring diagram clearly shows the wiring between the turn signal wiring in the steering column and the horns along with the color codes for the wires in your 69 truck.

Let us know what you find.

[91Bear]

It is probably best to work from the horn back to the steering wheel.
1. Figure out which wire on the horn relay is which. Wire 1 goes toward the firewall and is the horn ground wire. Wire 6 goes to the horns. Wire 33 goes to the battery at the starter solenoid post.
Okay. I've looked at the diagram but haven't matched things up under the hood so much.

2. Wire 6 goes from the relay to the horns. Touch a wire from the battery to the wire 6. The horns should both sound very loudly. If not touch the battery wire to the actual terminal on each horn and they should both honk loudly. If not they are not properly grounded or are bad.
I've done this and the horns honk loudly.

3. Attach a wire to a good ground point on the engine and touch the other end to Wire 1 connection on the relay. If you cannot get to the wire 1 connector, try placing a the test wire in the connector and plug it into the relay, then touch the other end of the test wire to the alternator. You should hear a very clear click of the relay and the horns should sound loud. If the horn does not make a solid click and sound the horns, either the relay is bad or the wire 33 is not supplying enough power to the relay. If the horns and relay sound loudly then the problem is further upstream toward the horn switch.
I don't have a test wire. I have some wires with alligator clips, though. Does the wire need to be a certain gauge?

4. Have someone stand next to the horn relay and try honking the horn with the horn ring on the steering wheel. Does the relay close with a good snap? If so the horns should sound. If not there is a grounding problem between the connector on the steering column for the turn signal wiring and the horn button/ring behind the steering wheel. In this case something probably mechanical is not right with grounding.
Right now, I can hear the relay click but the horns buzz or warble. The relay is new. I had to replace the voltage regulator so I went ahead and replaced the horn relay also.

5. I would make sure the engine is well grounded to the firewall by the flex strap that goes from the manifold to the firewall. I would next hook a wire to a ground point under the dash or on the firewall and hold it against the steering column at a bare metal spot. Try honking the horn. If it honks now, there is bad grounding between the firewall and the steering column. If it still does not honk clearly I would unplug the connector for the turn signal wiring and find the blue with yellow strip wire connection in the corner of the six pin connector (leading away from the steering column. This wire should be the same color as the wire going into the relay that makes it honk. Connect a ground wire to a ground point under the dash. If you touch the ground wire to the connector pin and the horn honks, the problem is in the mechanical switch ring or wiper contact under the steering wheel. That is all that is left in the circuit. I would take off the steering wheel and look for a bad wire or bad ground for the horn contact ring, or the wiper does not make good connection.

There is not much in the horn circuit. There are the horns which connect to the relay, the wire to the turn signal connector and the horn ring button assembly, which provides a ground to the relay. A good sounding horn that has a weak sound when the horn button is pushed is usually burned contacts in the relay. If the horn relay barely clicks or buzzes it is usually a bad ground from the horn switch to the relay.

As some people have pointed out, because of the age of these trucks, grounding problems can cause all sorts of strange problems.

The 1968horncircuit.jpg diagram shows the horn circuitry and color code for the wires. The 1967 master wiring diagram clearly shows the wiring between the turn signal wiring in the steering column and the horns along with the color codes for the wires in your 69 truck.

Let us know what you find.

Thanks for the help. The horn stopped working when my grandfather owned it. He died in 2003 and there was an auxiliary horn button attached to the steering wheel. I replaced the turn signal switch and it worked for awhile until it didn't. There's something else going on.

[zgerbic]

1. Figure out which wire on the horn relay is which. Wire 1 goes toward the firewall and is the horn ground wire. Wire 6 goes to the horns. Wire 33 goes to the battery at the starter solenoid post.
Okay. I've looked at the diagram but haven't matched things up under the hood so much.
[tony] The only things under the hood are the horns and the relay, which is next to the starter solenoid. The relay has three flat connections that plug into a three hole socket.

2. Wire 6 goes from the relay to the horns. Touch a wire from the battery to the wire 6. The horns should both sound very loudly. If not touch the battery wire to the actual terminal on each horn and they should both honk loudly. If not they are not properly grounded or are bad.
I've done this and the horns honk loudly.

[tony} Horns good. Next is to determine if you have a bad relay. The relay itself does not have to have a good ground. It gets power from the connection on the side of the solenoid and ground from the steering wheel horn switch. If needed I could go out to my truck, when the rain stops, and figure out which socket hole is which. There is an intuitive way to figure this out pretty easily. Measure the voltage at the three terminals. Only one will have 12V. That is the one to the starter solenoid 12V connection. It is wire 33 and provides power to the relay coil and power to the relay contacts that will power the horn when the relay closes. Two holes are left. If you take a small piece of wire, maybe 16 or 20 gauge and put one end in the 12V hole and touch the other end to the other two holes, one will honk the horn. This is wire 6, the connection that provides 12V to the horns to make them blow. The only other hole is the number 1 wire that goes to the steering column.

3. Attach a wire to a good ground point on the engine and touch the other end to Wire 1 connection on the relay. If you cannot get to the wire 1 connector, try placing a the test wire in the connector and plug it into the relay, then touch the other end of the test wire to the alternator. You should hear a very clear click of the relay and the horns should sound loud. If the horn does not make a solid click and sound the horns, either the relay is bad or the wire 33 is not supplying enough power to the relay. If the horns and relay sound loudly then the problem is further upstream toward the horn switch.
I don't have a test wire. I have some wires with alligator clips, though. Does the wire need to be a certain gauge?

[tony] Wire size is not that important, 16g to 22g would be just fine. The test wire is just a piece of wire with the insulation stripped back half an inch at each end. All you are doing is completing the circuit from the relay coil to ground, which energizes the relay to make the horn blow. The trick here is to use a small wire that you can put in the wire 1 hole and plug the connector back into the relay. What you are trying to do here is provide an alternate connection from the relay coil to ground to close the relay and make the horns honk. If this makes the horns honk, the problem is not in the relay but in the wire going to the steering column, trun signal connector or the horn switch itself under the steering wheel.

4. Have someone stand next to the horn relay and try honking the horn with the horn ring on the steering wheel. Does the relay close with a good snap? If so the horns should sound. If not there is a grounding problem between the connector on the steering column for the turn signal wiring and the horn button/ring behind the steering wheel. In this case something probably mechanical is not right with grounding.
Right now, I can hear the relay click but the horns buzz or warble. The relay is new. I had to replace the voltage regulator so I went ahead and replaced the horn relay also.
[tony] Step 3 will be useful. If the relay is new and assumed good, and the horns honk when the relay is bypassed, it points to the wiring to the steering wheel. If you can get step 3 to provide a temporary ground to the relay in place of the steering wheel horn switch, and grounding the test wire to the alternator makes the horns honk, then the problem has to be in the wire 1 connection between the horn relay and the steering wheel. I suspect the advice others have given that the problem is in the steering column area is correct, but you need to be sure the relay and horns are working in order to find the problem in the steering column area.

5. I would make sure the engine is well grounded to the firewall by the flex strap that goes from the manifold to the firewall. I would next hook a wire to a ground point under the dash or on the firewall and hold it against the steering column at a bare metal spot. Try honking the horn. If it honks now, there is bad grounding between the firewall and the steering column. If it still does not honk clearly I would unplug the connector for the turn signal wiring and find the blue with yellow strip wire connection in the corner of the six pin connector (leading away from the steering column. This wire should be the same color as the wire going into the relay that makes it honk. Connect a ground wire to a ground point under the dash. If you touch the ground wire to the connector pin and the horn honks, the problem is in the mechanical switch ring or wiper contact under the steering wheel. That is all that is left in the circuit. I would take off the steering wheel and look for a bad wire or bad ground for the horn contact ring, or the wiper does not make good connection.

There is not much in the horn circuit. There are the horns which connect to the relay, the wire to the turn signal connector and the horn ring button assembly, which provides a ground to the relay. A good sounding horn that has a weak sound when the horn button is pushed is usually burned contacts in the relay. If the horn relay barely clicks or buzzes it is usually a bad ground from the horn switch to the relay.

As some people have pointed out, because of the age of these trucks, grounding problems can cause all sorts of strange problems.

The 1968horncircuit.jpg diagram shows the horn circuitry and color code for the wires. The 1967 master wiring diagram clearly shows the wiring between the turn signal wiring in the steering column and the horns along with the color codes for the wires in your 69 truck.

Let us know what you find.

Thanks for the help. The horn stopped working when my grandfather owned it. He died in 2003 and there was an auxiliary horn button attached to the steering wheel. I replaced the turn signal switch and it worked for awhile until it didn't. There's something else going on.
[tony] It really appears to be a bad ground in the steering column. The ground connection might be there but have enough corrosion (poor connection) that the wire 1 cannot get the relay to stay closed solidly, allowing the relay contacts to buzz and not provide enough current to make the horns sound loudly. The switch on the side of the steering column was probably a band-aid fix for the bad grounding for the steering wheel horn switch. The button ground was probably much better.

[Fraser]

I'm new to this site, and neglected to look up the attached schematic before. Great resource, very helpful!
It sounds like you're making progress, I don't want to confuse things, but you have confirmed the pos. side of the relay as working. Often the remaining part is called ground, but I prefer to say negative, the horn switch finishes the grounding, this is the blue/yellow wire. Most Fords stopped using this system during the '60s, it's mostly just used on trucks by '69. Others used 2 terminals in the wheel for a positive circuit, and no relay.
Anyway, I would inspect the horn contacts for corrosion, twist off the button, remove the 3 screws on the back, and polish the metal contacts, also, there is a small, spring loaded brass contact in the wheel, about the size of a 22 casing, try grounding it, the horn should sound. If not, check it for a frayed wire. D.C. has them, part # C2OZ 13A821-A
The other concern I have is the T.S. switch you installed, some suppliers sell a "one size fits all" switch with 2 horn terminals, I'm not saying it won't work, but make sure you have used the inner ring.

Edit; I Think I have misread the above, finish testing the relay, then you are ready to move on, not trying to rush the progress.

[91Bear]

The other concern I have is the T.S. switch you installed, some suppliers sell a "one size fits all" switch with 2 horn terminals, I'm not saying it won't work, but make sure you have used the inner ring.

I got mine from Shee-Mar here: https://shee-mar.com/?page_id=293