Obviously that’s not correct, as the bluetooth card is built in, and should always be connected.

At first I though I just had a bad bluetooth card, but then I started having issues reading CDs and DVD’s in the optical drive and the lightbulb went on in my head.

Both these components are electrically connected via a mezzanine board inside the Mac Mini. There are some good pictures of this here at AppleFritter.com. Basically, to put memory into a Mini, you have to disconnect and lift off the subframe which contains the optical, hard disk, bluetooth, and a ribbon cable to the audio connectors, all of which connect via the mezzanine board.

To fix, I just popped open the Mini again, lifted the subframe and mezzanine board out then and plugged it back in, and everything was back to normal. It must have worked it’s way loose when I installed it, or due to thermal expansion/contraction after using it for the last year.

Moral of the story? If your Mini is acting weird, try reseating the internal components.