For no cruise AND horn button I suspect you have a bad switch inside the steering wheel. Some manufacturers (like GM) call this part a "clock spring". I don't remember what Nissan called it. I had this exact problem a few years ago on my 92 and, if I remember correctly, I took off the steering wheel horn pad/cover and replaced the CENTER clock spring switch. I'm sorry I can't remember more details regarding specific disassembly or the cost. ($50 -$65 me thinks) Check a Haynes if you got access to one. If you mention "center clock spring" to your parts guy along with the malady he'll probably get your meaning.
Hope this helped!