Q: Cannot add wireless Interface

2011 late iMac 27 3.4Ghz i7 Running El Capitan 10.11.3 When I looked at my Network under System Preferences, I do not see my Wi-Fi interface listed. When I go to add it using the plus sign, it appears in the drop down, but when I select create, it never appears in the list. In the System Report, it does show up as en1 AirPort Extreme  (0x168C, 0x9A). I am using my Ethernet for the internet, but sometimes I go to another room without an ethernet cable and connect wirelessly. I have tried to add another location, but it will not let me add Wi-Fi. Any one have a fix for this?