Power locks problem '96 SL1

Hi, I own a 96 SL1, and recently my power locks don't work anymore. When I first bought the car (about a year and a half ago), they did not work. Mysteriously when I was working under the hood one time, they decided to work. When I hit the unlock, the drivers side door unlocks, and thats all. When I hit lock, I hear the relay, but nothing happens. I just washed my car yesterday, and I'm thinking that might have something to do with it. So I ask, is this a fuse problem or a relay problem or something entirely different? And how can I fix it? Thanks.