My trunk will latch, but won't stay shut on 1993 Mercury Sable

I can shut my trunk and yank on it with all my might and it won't open. But after a few miles or a hard bump and it flings open. I disconnected the trunk release but it did not solve the problem. Do I need to replace the entire assembly, can it be adjusted, or should I just weld it shut?!?

Asked by for the 1993 Mercury Sable
you could try and adjust the latch