The clicking is more likely to be the cable jumping the sprocket, or a ratchet mechanism in the motor, (if it has one). When the car is new, you have to hold the switch which tilts the roof open then stops, you have to let go of the switch and push/hold it again for the roof to slide open, so there must be switches in the motor or a timer to stop the motor when it reaches its limits. As mine has been apart three times this no longer happens. I hold the switch and the roof tilts then opens all in one go. When it reaches its limits it clicks and I let go of the switch. I haven't taken the motor body apart to see why as I don't mind it working this way.