Hi!
The horn in my 1994 volvo 940 stopped working 2 days ago.
I checked the fuses and they all looks fine.
Any idea what went wrong and how to fix it?
Thank you.
Hector.

 

I had a similar situation, the low tone horn quit one day. I replaced them both.
EDIT
Also, check the bullet-style connections between the wiring harness and the horn. Those get pretty messy.

 

there should be power on the yellow wire to both horns if the ignition is turned on. it shares the power with the windshield wipers.

if there is power on the yellow wire, then grounding the blue-black wire should honk the horns, if it doesn't, the horns are probably dead. if there's no power at the yellow wire, check the wiring itself.

if the horns work when you ground them, then you need to check the ground circuit at the steering wheel, which involves a brush and slip ring. find that slip ring, and use a jumper wire to ground it (with the ignition on), if the horn honks, then the problem is in the steering wheel or brush.

 

Hi! This is hector.
I fixed the problem.
I removed the horns from the car, i disconnected the wiring and i put dialectric grease in the connectors, i hit the horns with a piece of metal, (in case that the horns were stuck together), i put the horns back in the car and tested them. They did not work.
Next day i drove the car to work and the horns started to work.
No failure so far.
Weir!!!!
Hector.

 

a friend of mine (who rebuilds ancient HD motorcycles), likes to say "If you can't fix it with a hammer, it must be an electrical problem."