I need help finding a movie?

It is a late 80's or early 90's film. I can only remember the ending, there is a man and he is sleep walking. He is dressed like a detective, he has a trench coat and a hat and sungles. He is carrying a briefcase or a treasure chest and he goes to the ocean and sinks but walks on the bottom. Two guys in a jeep I think are trying to catch him to take his treasure. I think a parade is going on at the same time. Please give me the title lol