Ice has been forming in the bottom of our side-by-side Maytag (MSB 2354 DRQ) which is about 7 years old. I noticed water on the floor under the fridge the other day. I broke the ice up and discarded it, and now ice has formed again. There was some ice on the back of the freezer cabin too, beneath the grille. It may have something to do with the defrost cycle. We don't have an ice maker.

Before I make a service call, I'd like to know if anyone knows what the problem might be, or how I could determine what is causing it. Thanks.