Once in a while 2011 ford focus makes a chime sound but nothing shows up on the dash could it be a glitch?

Once in a while 2011 ford focus makes a chime sound but nothing shows up on the dash could it be a glitch?

Could one of the doors not be closed all the way?

No. It may be any number of things.

It could be items on one of the seats triggering the seatbelt warning (bottled water can do it!) or ice warning. Is the speed warning set?

Faulty door switch - turn signal left on.