Trunk will not open?

So, I climbed in and opened the trunk. Found the latch connector not connected and the plastic trim around the striker off. Someone been there and was trying to just close it so it won't open. They did that because when you connect the latch connector the trunk opens fine. But the issue is, when you close the trunk, it locks the opens again on its own. For now, I found that when I close it and hold it down while it's trying to reopen for couple of seconds it will lock. Seems like the latch opens like it should not sure if this is a common issue where it just opens on its own. Before all that the trunk was not closing when I tried, it would not reach the striker. So, I adjusted the striker and now it closes but again it opens again on its own.

Latch works fine, I think the button which is a common issue has water inside it and shorted out. Can you find me the part number for the button that is outside on the 3rd brake light?