My macbook pro's airport is acting stupid. Help!

I bought a refurbished macbook pro not too long ago and it’s been working fine up to a point. For awhile now, I noticed that at times, the airport will stop working. At the top right corner, the wifi will turn off and the symbol will look as though I turned it off. When I try to select the option of turning it back on, it won’t come on. I have to restart or shut the computer down for it to come back on again. How do I fix this?