frigidaire pure source plus noise MODEL FRS24ZRH

The fridge has been working fine. 2 weeks ago it began to make a noise. Almost a clicking sound, it happens every 20 minutes or so and lasts about 10 seconds. Sometimes it’s very loud. It’s coming from the freezer side ( it’s a side by side) We vaccuumed out the back of the fridge. Took everything out of the freezer to see if there was ice built up, none that we could see. It sounds like something is trying to turn on, like a clicking everything is working fine cold etc. I don’t use the water dispenser and it has been disconnected for several years. Any ideas?