GE Monogram fan cycling on and off
We have a 6 year old GE Monogram side by side refridgerator. In the last 4-5 months I've noticed that I can hear a fan motor cycle on and off repeatedly for long periods of time. I can hear it ramp up, peak, and then ramp down...then back up, peak, and back down again. This continues over and over. Up until now the unit has been flawless and quiet. I can hear this fan cycle quite audibly. It's not super loud, but loud enough that I can pick out the cycle up and down sounds.
The unit doesn't seem to have any trouble maintaining the set temperatures in either the fridge or freezer sections.
We have completely emptied the fridge and freezer sections to make sure that there wasn't something obvious blocking a door or internal mechanism. We didn't really find anything and there was no improvement in the cycling noise.
We also pulled the fridge out from the wall space and thoroughly cleaned underneath and behind it, including vacuuming off any dust from the back side as well as from the motor housing that could be reached from the back side. No change here either.
Does anyone have any suggestions for us?
Thanks for any help,