Whats the flickering light on my freezer lid represent?

It flicker because the mains voltage fluctuates and, also when the compressor starts and runs you can see the light flicker as the current varies, too.

mmalky

It may be in the lamp socket...unplug the freezer and check the socket...lamps make contact with the outer shell and the middle tab..people screw lamps in as tight as they can each time pushes the center tab deeper and finally it arcs and doesn't make good contact again unplug the freezer and try and pull the tab up to make better contact use a Popsicle stick or non conductive material plastic spoon etc.. if the tab is blacken this is a sign that it has been arcing causing the flickering. TURN OFF THE POWER

Its most likely a neon lamp and with time they deteriorate and flicker and eventually go out altogether.

That its time for a new light bulb.