Unsuccessful fire rescue

Found a 3 d-cell Mag-Lite in a burn pit years ago.

Held onto it for years because the new colour intrigued me.

Came across another one today.

Not burnt but a swollen battery.

So I cleaned everything up. Froze the burnt one so the plastic would scrape off. Everything cleaned up great.

The swollen one was interesting to get that snap ring out but otherwise no corrosion to be seen in the switch.

So I swapped the orings, switch, lens, spring and reflector over to the burnt unit…new LED buld too.

I installed new batteries and gave my son the honor of hitting the button…nothing happened.

So…where did I go wrong?

What am I missing?

Does burning the aluminum tube all those years ago change how it works?

Did the temperature make it so it no longer registers the voltage going through it?

I took a picture next to potential siblings…6 d and another 3 d

Serial number puts it at 1992 to 1993, same as the unit I took the other parts from.