Olds. Achieva. Bad wiring?

I will assume you checked the signal/flasher fuse and go from there. This is a common indication that the multi-function switch has a problem. It's a fancy name for your turn signal switch which has other functions like cruise, hi/lo beam, etc. They are notorious for opens, short curcuits and thermal issues because the wires are very small gauge. At any rate, it is wiring in your steering column that is at fault. The horn is activated by applying a ground so the wiring for that is likely shorted to ground or the internal contacts in the horn button are broken. If your car has air bags, don't work on the steering column until you have disconnected the battery and made sure it can not make contact. An air bag deployment could kill you. There will be yellow wiring in the steering column and you don't want to mess with any of it. Make sure no one is in the driver's seat when you reconnect the battery to be safe. Hope this helps.