I had the same problem. I removed the drawer, replaced the latch mechanism, and it still wouldn't stay closed.
I went to Lowes and bought a Tee "T" drawer pull [stainless], drilled a 1/8th in hole, and placed the Tee between two drawers. When the top of the T is vertical, it will hold the two drawers closed. When the top of the T es horizontal, the drawers will open.
http://www.lowes.com/pd/Brainerd-Bar...nob/1002922884
JC