i cant unlock the doors using door lock switches from driver or passenger sides, but i can unlock the doors using keyless entry remoute. any idea?

Maybe check with a dealer to be sure, but if it's like the Continental I had (which shares some electrical bits)- the driver's door switch is the "master" and if it fails, the other front switch won't work either.

i replaced the master switch, but still is the same

Then you need to follow the wiring diagram- ensure there's power and continuity on the proper pins. You could very easily have a broken wire in the door jambs on either side.

Hi VTSummit, Could you provide more details? In addition, I want to tell that when I hit lock or unlock on key less remote most of time in driver door no locks move and it does not click well. Driver door power lock actuator most of time malfunctioning. I have a Lincoln Town car Ultimate 2004. Where can I find a free wiring diagram? Thanks.