Chances are it is simply a bad lid switch. Easy to get to and done from the front. Be sure to turn off the breaker to the machine before you open the washer up.
The manual for the stack models is here
. You may download it and follow the easy directions inside the document.
Unfortunately, you will not be able to order parts until you find the real model sticker, likely on top or side panel. It begins with 110. and has 8 more numbers after that. Also check in the dryer door for it, who knows...