I'm trying to get my horn to work to pass inspection.

Checked the fuse...good.

Removed the horn and connected to battery and horn works.

Used voltmeter to test horn terminals and got no response from the voltmeter.

There are two terminals on each of my two horns, one blue wire and one yellow wire. Can anyone tell me which is positive and which is negative?

If the voltmeter is showing no power at the horn terminals when the key is in the on position and the horn button is depressed I am assuming no power is getting to the terminals.

Also, I read on another thread that depressing the horn button grounds the horn causing the honk. If this is the case, can I connect the positive horn terminal directly to the battery and have a working horn?

Also, when searching about horn troubleshooting there is alot of talk about relays. I know how to access the relays but there's 9 of them and I can't find out which relay to check?

Any help I love you.

 

The horn relay is in the back row on the relay component thing, 2nd from the right. Left to right, it goes a big round one, a square one, the horn one (square), and then another one

 

Thanks melon. I'm off to check it out. How did you figure this out?

 

the relay is okay.

i connected the horn directly to the battery and it honked. so im going to have to rig something up to pass inspection. or take apart the steering wheel.

any thoughts?

 

Try the ground connections in the steering wheel. My 1994 940 had minor corrosion on them. I took out the air bag and jiggled all the ground wires. Also replaced the steering wheel switches.

 

Haha. I'm doing that now. As a last resort. Hopefully I don't get a broken nose from accident air bag to the face! I will let you know.

 

Alldata works wonders

 

I got the airbag out. Broke one of the torx screws because i was screwing the wrong direction...doh. anyway i can get one from the junk yard.

how do you remove/replace the wheel switches?

 

I got the switches off, snapped off. nothing too corroded in the switches or behind the airbag, but i cleaned them all anyway. Still no horn.

I am still wondering what the two wires connected to each horn are. One is blue and one is yellow.

I got the horn to honk with the blue wire connected to the horn and the yellow wire unplugged, and i used jumper cables to connect the yellow wire horn terminal to the negative post on the battery. I'm assuming this means the blue wire brings power to the horn and the yellow wire is the ground wire.

If the horn has power and honks when i ground it to the battery then where else could the problem be than behind the airbag?

Behind the airbag there were wires coming from each horn switch, leading to the steering column. one was fixed to the column (ground?) and the other went into a black circle shaped connector in the steering column and it had a spring action...if i pulled the wire out a bit and let go, it snapped back down. Anybody know what that is?

 

The one with the spring is a rotary joint. Try cleaning that. Look closely at the switches as they can get pitted. Try jiggling the fixed one. Mine was some sort of square contact that could be moved slightly. Also look at horn connectors for corrosion at the wire/connector. good luck

 

Well we got the horn working.

I used jumpers to ground the horns to troubleshoot. Starting at the horn and working to the steering wheel. Taking off the top vinyl panel of the steering wheel assembly was the breakthrough. From there I was able to leave the battery connected and confirm that the problem was indeed behind the airbag.

3PO was right it was the ground connection behind the airbag (which i cleaned thoroughly 2 days ago and had given up on. I removed the ground and bent it a little and cleaned it more and now the horn works.

I had to reconnect the battery while the airbag was off to test the ground connection and now my SRS light is on. So it looks like I have another project.

Thanks to all of you who helped me figure this one out.

 

Thx for this thread. I just pulled out both horns (blue/yellow, blue/yellow) that I put in only about a year ago, vowing I'd find a better place for them rather than the worst possibly place to disintegrate a piece of Chinese metal anywhere on the car. Mercedes puts horns in front of the radiator? Is that right, as memory serves, certainly better than in the front wheel well! My question is: since my son's brush with a guard rail already blew the airbags (not fixed, driving now without airbags, probably for eternity) I should have no problem removing the plastic plate on top of the steering wheel and checking the ground? That's good news. I may use another set of cheap horns to replace the rusted new ones, and use Blue/yellow, blue/yellow since the wires are there, but I'd love a tip on an improvement on the horns, a better placement, anything to not make this an Every Six Months event. Thx, DDay

 

I replaced the stock horns with FIAMM two tone kit and placed it (with some effort) on the sheet metal in front of the battery tray (just behind the headlight).
To do this, you must install a basic relay to power the horns through the original wiring. The OE wiring scheme does not provide enough power for the horns.
Works great!

 

Thx. Far as I know, there is a relay that covers the horns and a few other things on the relay board. When you "beefed up" your horns, where did you install the designated relay when you put your horns behind the battery tray, behind the headlights? How do you put in a designated relay? Basic wiring question. Thx, DSDVolvo

 

I placed the relay on the same sheetmetal support and wired the 12v side directly to the battery and used the OE blue and yellow wires to energize the horns. I'll see if I can grab a good picture, but the wires are now wrapped and loomed.

 

I can't get a good picture of the horn location because I had the headlights out when I installed them. The relay was installed with the battery out and I used a body panel clip to hold it in place.
Sorry, the pictures aren't too helpful.

 

Inspired by your story of putting in a separate designated relay for a More Powerful Horn, I bought two impressive-looking Big Red Horns (Pittsburgh brand) from Harbor Freight for $25 for the pair. They came with a relay, a typical relay with the normal male spades ready to be connected to power and the horn switch on the steering column. Before trying to connect with the wire in the steering wheel I tried simply hooking the Big Red Horns to the existing yellow/blue wires and using the exisiting relay which is shared with the windshield wiper motor and my driver's power seat. I'm concerned I may be asking too much of that set-up. I'm sure your separate relay is a better solution, but I'm going to allow the 25A relay doing triple duty to work on a trial period. It does work, though I do not plan to move my seat in a rainstorm while honking the horn! if I can help it! DSDVolvo
(It was fun building a better bracket for the Big Red Horns, however; I drew the line at figuring how to tap into the existing horn switch at the wheel.)
I'll take a picture of my new horns in the same miserable location where the existing wiring is, but with some rust cleaned up, I won't be driving through snow drifts, however, and expect the horns to blast their way through!

 

On my '95 940 the Existing Wiring through fuse #15, shared with the Driver's Power Seat AND the windshield wipers, does allow the new horns to blast convincingly . however, as i cleverly quipped: "I don't plan to adjust my seat while tooting my horn to announce my arrival in a rainstorm!" What I don't really know, regarding the strength of a 25A fuse is: could I do just that: Toot, Adjust and Enjoy Wipers Cheerfully Slapping Time with Bobby's body next to mine as he plays the harpoon wrapped from within his dirty red bandana. (Me and Bobby McGee, Chris Christopherson via Janis).
[img alt="Musing on the different fuse set-ups in similar 240s and my 940 and wondering about How Much Is Too Much to Ask of the #15 fuse on a '95 940?
"]https://cimg6.ibsrv.net/gimg/volvoforums.com-vbulletin/1540x2000/volvo_x_5_horn_fuses_relay_how_much_is_too_much_on _a_fuse_with_multiple_uses__dddfa1c1e3466da16f5f37 9c56c2d8751a6f75c3.jpg[/img]
Musing on the different fuse set-ups in similar 240s and my 940 and wondering about How Much Is Too Much to Ask of the #15 fuse on a '95 940?

 

Graphic version of the words above re: horns.