My passenger side low beam is not working. However right low beam is working, and both side high beam are working. I swapped left right side bulb and fuse. The problem remains the same. So it's not bulb and fuse problem. What else should I look at?

 

Have a volt meter?

Test to verify if you are getting power and ground - the ground "point" for low is the same as high so it should be good but you have to verify there is not a "break" in the wire going to the ground point.