I am not an expert, but have had this problem, it's caused by opening the door while it's running, causing a pair of small sensors in the fan caseing to blow. Explain the problem to your local repair shop, insist on buying the parts. Take off the fan caseing, then change them one at a time, they look similar but are slightly different, compare the No on each, then change.
Ted Marillat, September 2012
