Freezer intermittantly warms and blue temp setting...

Question

Freezer intermittantly warms and blue temp setting lights on inside of frige door and the top interior light for frige do not always work. Purchaed used and did not notice lack of blue light until several weeks had passed...only noticed when the light was on yesterday for a short while. I thought maybe a disconnected wire to that area but the filter indicator ligh has always been on (green). Any suggestions as to how to fix? thanks.