My best guess would be a problem with the dowel pin sense switch, it is on the drivers side of the windscreen down in the hole that the big dowel pins on the front of the roof drop into. If memory serves it is a two position switch. The first position senses the roof is resting in place, ready to lock and once the lock is applied it senses it fully down and secure. You might find the top will reverse into the open position, and this would allow you to double check there are no obstructions. You could also put a screwdriver, biro into the hole and feel it click. If your scan tool allows it might even show the switch setting and let you see it toggle when pressed.
If it were mine I would
Good luck getting it fixed. From the service manual...
If it were mine I would
- See if the top will open so that I could check for obstructions
- Manually probe, test the switch function
- Move the top into the closed / resting position and see if wiggling / applying gentle pressure makes a difference. Remember the sense switch could be faulty, it could be the top is not pushing on the switch at all, or pushing too firmly so the top is considered locked when it should be resting.
Good luck getting it fixed. From the service manual...