I'm wondering if it's the switch. The guides could be cleaner, that's for sure, but I don't see the minor debris in those as a viable explanation for the sunroof coming to an abrupt halt after opening just fine, then closing just fine up to the halt point (about 90% closed position). If something was actually blocking a guide, I think I'd hear the motor struggling and groaning. Make sense. Looks like we'll try a switch and report back.