Do what bluelightnin6 said about checking the fuse. Then, if you hear the relay click under the dash board, you know the switch is working. The fuse has to be good to for the relay to click. The only possibility then is a broken wire or TWO bad horns. There's a low note and a high note.
There's two other common causes of a dead horn. If EITHER horn is shorted, it will blow the fuse when you press the button. In that case, you will not hear the relay click. When vehicles were out of warranty at my dealership, we sold customers universal horns with a choice of two mounting brackets. As I recall, I think they cost less than 15 bucks each. You must specify low or high note. You can unplug one of the horns, then install a new fuse and try it. 50 / 50 chance you unplugged the shorted horn. If the fuse still blows, unplug the other horn and try it again.
The second common problem is a broken clock spring under the steering wheel. The old sliding contacts that were needed so you could turn the steering wheel without twisting and breaking wires had many microscopic intermittent connections that could delay operation of the horn so slightly that you would never notice it. With air bags in the steering wheel, they can't take a chance on those contacts. The air bag must fire at the exact microsecond required, so to insure a solid electrical connection, a wound-up ribbon cable is used. That cable includes circuits for the horn and the cruise control. If the clock spring is the problem, you will not hear the horn relay click, and the fuse will not be blown. In addition, as the ribbon cable continues to break, the cruise control will not turn on and / or the air bag light will come on.
Don't panic about the air bag light. The system is disabled when the light is on. It won't pop in a crash, but it won't pop unexpectedly either.
Friday, December 4th, 2009 AT 1:39 AM