On an early version it is bad gears, later version it is bad bushings in the gear housing.
No, it is in the gear housing on the motor. Something is slipping, so not sufficient resistance at first for the motor to stop working right away. It wll just get worse if not fixed. 84-86 years need new gears, 87-96 need new bushings. A one hour DIY job and just a few dollars for the delrin bushings.It sounds like it keeps trying to close the light even though it's closed. Maybe a dirty relay?