What would cause the horn to stop working on a Ford E-250 van?

Answer 1

Horn ProblemBlown fuse, defective horn, defective horn switch, or loose wire.

Check your fuse first. If that doesn't appear to be the problem, then you have to troubleshoot. I think that I would start my troubleshooting right at the horn itself. I would run a hot 12v lead from the battery terminal to the horn and tap the terminal to see if the horn responds. If you do not hear the horn trying to honk. I would replace the horn. You might also want to have someone press the horn button while you hold a 12v test light on the end of the horn wire at the horn itself. If you have power reaching the end of the wire, then the problem is surely the horn. You may want to check to make sure the horn is properly grounded as well. It is a pretty simple circuit and its most likely to be a blown fuse or a bad horn. Some other things that could cause this is a short in the horn circuit, most likely inside the steering wheel cover. If you do not have a blown fuse and you have no power reaching the end of the wire when the horn button is pressed, then you should disassemble the steering wheel cover and observe the horn wiring inside for any breakage or corrosion.