What makes the ashtray lock into place, and unlock?
 

When I have my ashtray assembly out, it works fine. When I push it into its proper spot where it has pressure on it from other parts around it, it won't stay closed; the little locking mechanism doesn't click into place then.

What would cause that? If I could see how the little lock works, I could figure out what's causing the problem, but I can't see anything. I did make sure to stuff the cigarette lighter wire way back in, behind the metal bracket behind the ashtray to make sure that's not impeding anything.

1991 300d, 182k

Answered my own question!
 

I took the ashtray assembly out all over again, and found that the locking mechanism is not on the inside; it's on the outside.

I could see the little lever was abraiding the assembly, preventing it from springing as it should, so I shot a bit of lithium on it, and it works like a champ once again!