What would cause all the turn signals and horn to stop working suddenly?

Answer 1

Have you checked the fuses? If the horn and sugnals are on the same circuit, that may be a simple fix. If it isn't a fuse, it is possible that there is a relay which controls both. A schematic, as found in some repair manuals should help you, if neither is the problem. Could be a bad comon ground wire or something else-you didn't specify make/model/year, so all that anyone can do is make educated guesses. It may be a fusible link if they're both on the same circuit. If you've checked the "easy" fuses and they're all seemingly good, I'd check any fusible links your vehicle may be equiped with. I had a fusible link (on a 1990 Cherokee) fry and it took out my headlights, taillights, brake lights, hazards, driving lights, dash lights, interior floor lights, all "indicator" lights, and the cigarette lighter--but the turn signals, dome lights (I have two) and map/reading lights worked fine!