I have a 2003 f 250 superduty crew cab lariat. I believe I have a loose connection or a faulty door switch because the curtosy light stays on and the open door symbol on the dash stays on. Where is it located within the door and how hard is it to access it.

 

The door ajar switch/s are mounted in the lower portion of the door latch.. They tend to stick over time from weather/debris.. Try using a silcone lube ect. and spray the door latches liberally concentrating into the lower latch area/s.. Bump the door closed/opened and in most cases the switch will come loose..