If it is same drive unit as on later models, there is a white knob on
the drive unit, which can be pulled out to "adjustment position" and
turned slightly to one or the other side to adjust the sunroof settling
position.

Each time after adjusting, it must be pushed in before trying the
operation.

When pulled out, the drive unit is disengaged from the sunroof cable,
and when turned a little, it adjusts the position of the drive gear,
which actuates some microswitches to determine the closed position of
the roof.