I have a Sears model number 139.53615SR. When I push the open/close button, I hear a click and the light comes on. The motor does not run and the trolley is not jammed. Any ideas?

The most likely causes are (1) burnt-out motor, (2) broken motor wire or dirty/loose connector, (3) faulty limit switch, and (4) faulty relay in the controller. You'll need a multimeter (and know how to use it) to distinguish between these possibilities. There are further possibilities, but these are the most likely.

Daniel