Touchpad not found after replacement

Hi all -

Original symptoms were short battery life and touchpad physical clicking not working. I bought a replacement battery and touchpad.

Battery was definitely bulging and putting pressure on the touchpad. I swapped out both and when booted back up - no mouse movement or clicking at all from the touchpad. External mouse works fine, so I went into system preferences and then Touchpad. It said "Touchpad not detected" or something along those lines and had a spinning circle indicating that it was searching for bluetooth touchpads.

So I opened it back up and swapped in the original touchpad - mouse movement but no clicking. But still, system preferences says it doesn't detect a touchpad (I was hoping to at least turn on tap to click.)

So, what am I missing? Is there some extra step to set up the touchpad with the OS? Does the lack of movement on the replacement pad mean that it's DOA?

Thanks for any help!