Can driver side doors from a 2004 fit a 1999
Absolutely. 1998 - 2004 Intrepid doors are all the same.
Door wiring connector will be different.
You'll have to double check that but I think they changed the size/shape of the connector after 2000 or 2001.
Connector size shape at the front will be different size/shape. Just swap over you existing door wiring harness to the "new" door. You'll also need to swap door lock cylinders which is easy so you can use your existing keys. Interior door panels will probably be different colors so those also interchange easily.