Maytag bottom freezer fridge periodically stops cooling

Hi.
My fridge stops cooling, periodically approx. every 3 weeks.

The first notice I get is a louder click and then a buzzing sound for approx 10 - 15 seconds coming from probably a rely very close to the compressor ( it is almost attached to the compressor). During the buzzing time the lights inside become dimmer. After the 10 –15 seconds the buzzing sound stops following a second click from that rely.

The process keeps repeating, the fans keep going and the temperature goes up.

I then need to unplug the fridge for a night and when I plug it in next morning everything works fine for another 3 weeks.

I will appreciate any advice. I hope to be able to get a proper part and replace it my self.

Thanks a lot,
Les