It may be something very simple like this
For this tip to work you have to have an operational sunroof. If your cable is damaged or the motor is not running or your tilting arms are bent or broken this video will NOT help you. If your car is parked outside and it has been ages since you cleaned the seal then this could be a "miracle cure." This procedure primarily works best on those tilting sunroofs on Mercedes from 1986 to 1995.