You will see the blinking yellow light if the Airport base station has been reset. Sometimes, you are unable to connect to the internet the yellow light can mean that the cable modem of the Airport device is unplugged. Lets see how to fix Airport extreme flashing yellow.
Steps to resolve flashing yellow light:
Switch on your Mac and make sure it is connected to the Airport.
Now, click on the Wi-Fi icon.
Then, open the Airport utility application.
Check the name of the base station.
Follow the onscreen process to setup the network properly.