If it has the b43 module...
modprobe --list | grep b43
...then I would install the firmware for b43. If you have a wired NIC connected to the Internet while in Fedora, the steps people often use to install the firmware are...
tar xjf broadcom-wl-126.96.36.199.tar.bz2
b43-fwcutter -w /lib/firmware wl_apsta_mimo.o
After that, reboot or restart NetworkManager and check for networks. If it doesn't work at first, then return here for some things to try for it.
If you can't connect Fedora to the Internet by wired NIC, then use another operating system or computer to download that tarball in the first step. Somehow transfer it to the Fedora filesystem and pick up the steps with the tar step. If it doesn't work at first, return here to try some things known to help.
Some BCM4312 versions apparently don't work with b43. If you never get b43 working (or don't want to try), then you can compile the Broadcom 802.11 STA Linux driver available from Broadcom's website.