On a clean install of Lite 15.3 32 bit, Zorin did not detect the Broadcom 43xx wifi adapter on my Dell D620. After some research, I found this procedure on the Mint web site that ended up working for me 100%. You might want to check it out. I have resurrected my D620 because of it.
Thank you for sharing the solution. I hope this helps many users with the Broadcom wifi adapter. It's a constant hope that more would search and share as you have. I look forward to your future posts.