Lexus IS300 Sunroof / Moonroof Stuck, Clicking Sound *FIX* | More info
If your IS300's sunroof is stuck in any position and if you can hear an audible click near the map light when the sunroof controls are pressed then this video may help you fix your sunroof issues.
My IS300's sunroof was stick in a tilted open position. The copper contacts on the inside of my sunroof's drive motor had carbon build up and was stopping the motor from operating.
Here is the picture of the white gear and the position that it should be in when the sunroof is completely closed.