They rarely require a slam. You can soft-close the door, then lean on the outer edge enough to engage the latch. Often, the door just isn't aligned correctly.

They rarely require a slam. You can soft-close the door, then lean on the outer edge enough to engage the latch. Often, the door just isn't aligned correctly. Either it's sagged on it's hinges over time, or the latch itself needs a minor alignment/adjustment (Note that even on a lot of new cars, this still helps a lot! Not all manufacturing is perfect). Other times the rubbers can be hard and perished and it doesn't allow the mechanism to engage properly.