Hello from Just Answer and the Appliance Catigory
My name is Woody.
I will be glad to assist you today.
I have been servicing ALL Major Brands of Appliances for 36 Years, I own my own Appliance repair Company
And I teach appliance repair at a local Community College.
I have over 100,000 plus in home repairs and over 80,000 internet repairs under my belt.
You will be paying me for my ANSWER to your Appliance Question,, Not for the repair of your appliance hence the name of this site Just Answer.
I will do my best to take the information that you provide to me and make a Diagnosis for you to be able to repair your own Appliance.
I would assume that you have an issue with the door latch / switch were it may not be making good contact every time the door is closed and the latch brought over to engage the operation , they latch arms can become bent or just wear out just enough so as to lock the door but not to engage the door switch for operation .
I recommend to replace the door latch assembly on the top of the door.
The link below is to the part you will need from a highly recommended company rated A+ with the Better Business Bureau.
They offer a 100% money back guarantee, EVEN ON INSTALLED ELECTRICAL PARTS, for an entire year!
They are the only company to allow returns on installed parts for a refund and offer a FULL ONE YEAR WARRANTY!
http://www.repairclinic.com/PartDetail/Door-Latch/WD13X10003/771030?rcaid=1000070 this parts link even has a video on how to replace the assembly and can be done with basic hand tools.
If you have any questions just reply back.