It sounds like the same problem I have had several times. The cooling fan in the fridge compartment becomes clogged up with ice and eventually freezes solid. Have you noticed that the fridge does not cool as well as it used too, particularly on the upper shelves? If so then you will need to unscrew all of the fridge section internal back panel and water cooler (obviously with power turned off!), unclip power connectors and then remove the main unit with fan inside...if its frozen solid you may need to let it defrost some more. Once all removed, suggest using a hairdryer or fan heater to melt all of the ice. If you have time on your side then an even easier approach is to simply power off the whole unit for about 3 days so that all of the ice melts away.
Paul., January 2009
