My son and grand son are executers of my will Which is solely house hold contents .Do they need to file the will with probate?

The answer to your question will be evident after you pass away.  It's difficult to answer it now and especially without seeing the will or knowing more about your assets.  I would not recommend naming co-executors of a will if that's what you've done.  My philosphy is one chef in the kitchen at a time.