The sunroof on my '88 735 slides real easy on the track as it opens and closes. When it get an inch away of closing, it stops. It's like the motor thinnks it is at the end of its cycle and is closed. When I get the Allen wrench out to close it all the way, it closes with ease which tells me there is nothing binding it on the track. Is there a trip switch, like on a garage door opener, that might need to be adjusted?