The switch should be wired just like the old one– whatever wire went to L goes to L, whatever wire goes to 1 goes to 1, etc.
Am I understanding that the original switch only had three wires? There are two different types of 3 wire switches, one for 2 speed fans, another for 3 speed fans. How many speeds is your fan supposed to have?
PS what make and model is the fan?
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