moon roof switch test

I almost purchased a new moon roof motor, jumping to conclusions again!! I discovered that it works after testing it. I pulled it apart and gave it direct power, and it works! So my question is what is wrong with it? It's fused through the same fuse as the power windoes, correct me if I'm wrong but if my windoes work the fuse is OK! I am now left at the switch, But I am not sure how to test it.