My dell xps 13 has a broadcom 4352 wireless adapter. It used to work (though not so well) with an automatically installed proprietary driver Broadcom 802.11 Linus STA wireless driver from bcmwl-kernel-source.
Yet not so long ago, it suddently stopped working, after an Ubuntu update I guess... the wireless tab in the settings either won't appear, or it says that there is no adapter.
I tried the fixes proposed in other posts, mainly starting from this one: Installing Broadcom Wireless Drivers
so I tried to reinstall the driver I used with the software updater, to install the driver manually from command line, I played with the modprobe command and the associated blacklist.conf file to block other drivers that may interfere (bcm43xx, b43, b43legacy, ssb, brcm80211, brcmfmac, brcmsmac, bcma). I tried various possibilities but without success.
I tried also to use Ndiswrapper (https://help.ubuntu.com/community/WifiDocs/Driver/Ndiswrapper) to install the windows driver but couldn't find the .INF file for the driver neither unpack the .exe file that comes from dell support (tried cabextract and unshield as suggested in the instructions...)
Using the command rfkill list, I used to get two wirless devices displayed, one called phy0 and the other bwl I think, now there is nothing displayed.
Do you have advices to start from a clean situation and try again from 0? For now I have the feeling it is all messed up with various drivers installed and blacklisted items...
Thank you for the help! It is really great to be able to ask questions here!