Hello All:

1967 Volvo 122S wagon. I have been trying to get the horn working on this car. The previous owner told me the trouble was with the foam spacer in the horn ring. I took the ring assembly apart and indeed, there was basically hardened clay where the foam ring once was. I cleaned to a shiny finish literally every piece of the ring assembly, inserted my new foam spacer as suggested elsewhere, and reassembled the beast. Still no horn.

I have traced the electricals as diagramed in the manual and everything seems right: brown and black from the passenger side horn, merging with another brown and black at the driver side horn, the black goes into the steering box where it emerges from the wheel at the spring wrapped contact piece which contacts the steering wheel. On the brown side, it goes into a multi connector, emerging out the other side and into a wire harness that feeds it to fuse 2 in the fusebox. I know that when you activate the horn the connection goes to ground at the steering wheel and the horns should sound, but no such luck. I took off the ring assembly and tried to make a connection between the wire end contact and a grounded part of the car but again, no luck. I also tried to bypass each horn by removing the brown and black wires from each and completing the circuit by holding the wire ends together. Yes, with an assistant activating the horn and yes, with the ignition on.

I am satisfied that the wiring is correct which makes me wonder if the horns themselves are the problem. It seems unlikely to me since the car is in incredible original condition (less than 80K original miles) and everything else works, absolutely everything else.

I have a multimeter and I am ready to start testing every component but I am not sure how to do it. I understand the basics of electricity including having read the SWEM piece but I have rarely used my multimeter before. Right now I am getting millivolts across the horns. What do I check? Voltage or current? How do I test each of these horns as well as the other components in the system?

Cheers,

Jeff Pucillo

Jeff;

Electrical devices only work when there's voltage ACROSS the terminals, so unless the IGN was ON *, and someone was pushing on the hornring at the same time you were measuring, you would NOT see 12V...you read millivolts because without the hornswitch being closed, there was no complete circuit on the chassis side...try measuring the brown (IGN supply) wire TO CHASSIS again with the key ON...then you should see 12V there...do this first to establish the supply side...

...then, with meter in resistance or continuity beeper mode, measure resistance/continuity to chassis to establish the ground side.

...having established that voltage is across the horns, and that they don't work (most of their life, they're just sitting there corroding away), it's time to replace, or refurb...

The horns are an electromagnetic device so polarity determines the pole of electromagnet...if this is attracting/repelling a permanent magnet, polarity would matter, but since (I believe) they are only working against unmagnetised iron, I would say magetism is magetism, so polarity don't make no nevermind!

Naturally, horn connectors, which are under constant corrosion attack are one of the best places to use zinc anti-corrosive-paste...but you knew that, having read the horn, and likely the ACP articles...

Waggin; Horns are set up to vibrate...as the armature moves, it opens that breaking contact breaking the current, and the armature relaxes, closing the contact again, allowing the current, making magetism, moving the armature etc. ...kindof like lather-rinse-repeat...so that breaking contact (and the ability for the armature to move freely) are all critically important to the workings...unfortunately horns don't get excercised nearly often enough to keep the inevitable corrosion from freezing them up...the old ones at least have screws which allow you inside to to a cleaning and refurb...newer ones are swagged closed, therefore a throw-away item. If you freed yours up, good on ja!

Cheers

* Horns (as well as barke and reversing lights) are supplied by Fuse2 which is an IGN power function (please take note, Phil)...for reference, see: http://www.intelab.com/swem/122S%20Wiring%20Diagram.jpg

Hello Ron:

I am glad you posted when you did. I am on location out-of-town so my internet access is sporadic; the good news is I have Virginia with me so there is plenty of time to tinker.

Despite the IGN function discrepancy, Phil's post was very helpful and I tried several things this morning. First off, I checked to ensure that the reverse lights come on, ensuring a functioning fuse 2. Unfortunately, I did NOT have an assistant push on the ring when I did my voltage test of the brown lead. I will try that again tonight.

I went 0-for-3 on all of Phil's tests and here is where I need help, folks; I tested the horns on the battery and neither worked. I nearly gave up but decided to take them apart instead. I have heard that the screws get frozen but that was not the case here. I do not believe they were ever opened, it is just that Virginia has truly been babied.

When I got the passenger-side horn open I found the breaker contacts were corroded together. Not really knowing what I was looking at I lightly cleaned them and reassembled the horn. I retested on the battery. Still no sound. Defeated, I was about to put the whole kit-n-caboodle back on the car when I decided to open the driver-side horn. Same deal, corroded breaker contacts. Considering the IMMACULATE condition of the entire inside of both horns (they literally look like they were assembled on Sunday) I decided the breakers had to be the key. This time I unscrewed the entire breaker contact arm and really cleaned the junk off the contacts. I reassembled the horn and tested it on the battery. Still no tone.

CRAP.

However, I think I figured something out, and Ron's post backs me up. When I reassembled the horn the contact breakers were physically forced together. As I enjoyed my five hour drive to the new location today, I decided there had to be some kind of "field energizing, collapsing, re-energizing, opening and closing breakers" kind of phenomenon happening inside the horn. If the contacts cannot open and close, there is no way to have the horn sound. So, why can the contacts not open? Bueller? Anyone? I suspect that the previous owner was experiencing the stuck horn problem and turned the "adjustment screw" on the back until the contacts were mashed together, silencing the horn but also bending the contact breaker armature. Does that sound like a reasonable theory? If so, I am going to try to create a small amount of clearance between the breakers. I am measuring 12V across the exterior contacts.

Sorry for the long post everyone.

Cheers,

Jeff Pucillo

Hello All:

Just to let you know, I tried the brown wire voltage test with ignition on and I did not get 12 volts, only millivolts. I then took apart both horns and tried to adjust the breakers, testing each setting by putting one horn contact on my negative battery terminal and running the other terminal through my multimeter (set to DC) to the positive terminal. No matter what I did, no matter how I adjusted the horns, no noise, nothing. I have spent about five hours on this project, far too long in my opinion, and so I bolted the horns on my car with the intention of ordering new ones when I get home.

On my way out of the driveway tonight, I pressed the horn ring and you can probably guess what happened. One of the horns sounded. It is clear that I need to adjust the other horn and I am in business. I do not want to wake the crew so I will try it in morning.

You have all spent a lot of time and energy helping me with this, and for that I am thankful. At the risk of sounding needy, I am a bit frustrated by the fact that I am not successfully testing my components, although I can successfully test the voltage of my battery all day. I was also able to test the resistance of the breaker contacts inside the horns to ensure they were opening and closing. If anyone has any insights as to why the horns did not sound the way I tested them, I would love to hear what you have to say. Again, thanks.

Cheers,

Jeff Pucillo

Jeff;

If I understand your explanation correctly, I'd say your method is at fault...a Voltmeter is used to measure voltage, and not pass current...by placing it is series with the load..."running the other terminal through my multimeter (set to DC) to the positive terminal" ...remember, a currentmeter must pass all the loadcurrent, so be in series, a voltmeter sniffs the voltage...typically you connect its neg lead to ground/chassis, and then sniff around for voltage with the positive probe. That's why you always refer to a voltage reading as: ...voltage across....

Suggested reading: http://www.intelab.com/swem/an_automotive_electrical_primer.htm

Cheers

Hello Ron:

I am embarrassed to say that I did indeed read the electrical primer about two weeks ago. I found it so helpful that I printed it out and added it to the back of the electrical chapter in my Amazon manual. The voltmeter method of (not) passing current is almost surely the culprit; I used it only because I do not have a wire here. I am staying in an abandoned house until tomorrow so I am limited to the tools I had the foresight to bring.

Thanks again for all of the responses.

Cheers,

Jeff Pucillo

Horns (as well as barke and reversing lights) are supplied by Fuse2 which is an IGN power function

Oops... yes, on a 122 that's right. On 1800s they're hot all the time.

I had the same problem with my horns. No noise... but tested both by hooking up directly to the battery terminals as recommended by another. Cleaned up connections, ground and fuse and got the high horn to work. Some suggest a spray of WD-40 into the opening - I did that as well.

The low horn (passenger side horn) was a different story - nothing seemed to work. I opened it up (took some doing as the bolts were nearly frozen on) - inside is something that looks like breaker points - I used sandpaper to clean up the points, put it back together and it worked! There is also a phillips screw at the back that tunes the horn - I loosened it a bit I think and that helped clear the throat as well.

Both high/low horns sounding together - sounds really sweet.

waggin.

65 120 wagon, 85 240 turbo wagon

Jeff,

As you figured out, the black is momentary ground from the horn ring. Brown should be 12V full-time, even with the ignition off.

I would disconnect the brown from both horns and check for 12V from the loose end of both brown wires to ground -- the chassis of the car, not the black wires. If that's not there, you've found the problem.

If you do have 12V there, check for ohms from the black wires to chassis ground -- it should be an open circuit (infinite ohms) until your assistant presses the horn ring. Then it should read close to 0 ohms. If that's not there, your horn ring is not making contact.

I'm not sure if it matters which terminal gets the black and which the brown, but you won't blow anything up experimenting. Do the left horn first with the right disconnected and try it both ways if both of the tests described above check good.

All the foam spacers do is keep the horns from shorting to ground.

Surest horn test: across the battery. Remove horn, put a wire on the terminal and the + side of the battery, hold the horn bracket (scraped clean in one spot)on the - side battery terminal.
After all that silence, you will probably hit your head on the hood when the horn unexpectedly blares.

Hello Al A:

Wow, thanks for the quick response. The horn has two terminals; does it matter which one I use?

Cheers,

Jeff Pucillo