2000 Sle P/s Failure

P/S quit instantly. No noise, no fluid leaks, Fluid level fine. I suspect the pump but was wondering about the speed sensitive steering. Is it possible that it's a sensor and not the pump? I don't want to replace the pump and find the problem is some place else. Anyone had/heard of this problem. Believe it or not this happened before I could pull it in the garage to start drying it out. (Previous post 12/12). The car has 97K and I like it but seems like the problems are starting to mount. Thanks for any help.
Mitch Armentrout

12/19 My neighbor who is an autobody man says he has heard of the presure relief valve failing so the pump can't build pressure. Anybody else out there seen/ heard this problem?

Power steering fixed. Shaft in pump broke off deep in the pump where it attaches to the pump vanes. New pump on problem solved.