2006 Volkswagen Touareg Trunk auto lock

Interior problem
2006 Volkswagen Touareg 6 cyl Four Wheel Drive Automatic

My trunk has an auto lock (so when I go to close it, I don't have to do it all the way, because as soon as it gets close enough, the latch activates and the trunk closes itself. Lately, the latch hasn't been activating at all. I have to close it all the way down myself. It wouldn't be a problem, but I often have to transport big objects in my car, and when it latched, the trunk was able to close. Now, I physically do not have the strength to close the trunk, and it does not latch, even when there is nothing in the trunk. I know the problem--the latch is broken! I was just curious as to how that latch worked in the first place? What are the mechanics behind it? Thank you.