The part(s) or condition(s) listed below for the symptom Trash compactor drawer won't close are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The roller helps the compactor drawer to open and close smoothly. If the roller is broken or damaged the drawer may not close all the way. Pull out the drawer and inspect the rollers. If the rollers are broken or damaged they will need to be replaced.
If the compactor drawer will not close, there may be trash buildup or something may have fallen behind the drawer. Pull out the drawer and make sure there is nothing prohibiting the drawer from closing all the way.
Some trash compactor models have a door strike and catch to help keep the door closed. If the door strike or catch is broken, the damaged component should be replaced.
The trash compactor drawer rides on rollers and rails. The drawer may be difficult to fully close if the rollers or bearings are not turning freely or if the rails are bent or sticky with old grease. Try cleaning and regreasing the drawer slide rails first to see if that allows the drawer to open and close more easily. If one or both of the drawer slide rails are bent or damaged, the part should be replaced with a new one.