Mavericks menu bar Wi-Fi icon does not refresh
Here are few steps to try-

A- To check your functionality  run the 

airport -s


in Terminal. 

That should show you the scan results.

B- If there are no results check your hardware profile in About this Mac (this is mine)

Card Type: AirPort Extreme  (0x14E4, 0xE9)
  Firmware Version: Broadcom BCM43xx 1.0 (5.106.98.100.22)
  MAC Address:  14:10:9f:f0:29:8c

Check the com.apple.airport.airportutility.plist for been up to date (recent) or just delete it.

C- If above worked then your WiFi Icon in the menu bar is broken.

Press and hold the cmd key and drag the WiFi Icon to desktop (and it will vanish).

Restart.

Go to 

/System/Library/CoreServices/Menu Extras


And click on 


  AirPort.menu


That will bring your WiFi Icon back (hopefully working this time).