99 PA sunroof problem

My 99 park avenue's sunroof automatically opened when I was started up the car, and could not be closed using the control. Ocasionally, the sunroof was closed automatically when it was parked. But when I started up the car, it would be closed again. The control for it is totally disfunctional. What is the possible reason for this and how do I solve it? Thank you!

Does it open every time you start it? Does it shut everytime you shut it off?

No. Since it opened last time when I start the car, it has been kept open.