I pm'd Jeff.
Jeff if you get this, these are off a Kennedy. I tried to call them but it's after hours. I've heard people say they charge a lot for replacement locks, if this is so, is there somewhere cheaper? I have the lock number, it's a 100 series, the kind where the cam rid inserts directly into the back of the lock...
It's already gone, but the one lock still doesn't work. I'm just curious as to what fails inside these--it's not the first time I've seen it. It doesn't matter I'm just wondering.
The damage is when one of the pins (or more than one) gets worn enough that the two pins in that stack (the driver pin and key pin) shift and where they meet (called the shear line) no longer occurs at the shear line of the plug (center part of the lock). It is then like it is the wrong key.
If you take the lock to a competent locksmith, he can replace the pins in the lock. Since you have the lock already removed from the tool box, it should be cheap to repin.
Would also be a good idea to have them cut another couple of keys to replace the worn/damaged keys, which is likely the cause of this issue in the first place.
I bought a set of five keyed alike on eBay for my boxes. One day I discovered that somehow the lock on my bottom box was turned between locked and unlocked. Couldn't get the key in, so I drilled through the lock. I had a spare, so I was OK.