Dome light doesn't come on when door opens

Hi there, I just got a 98 Pathfinder LE and have noticed an odd problem.
The door switches on the drivers side, front and rear doors, don't activate the dome light when either of the doors are opened.
Passanger side doors when opened will turn the dome light on.
Am I unlucky enough to have two bad door switches (neither is corroded by the way) or is there another problem?

Thanks

B

Check for a bad ground wire to the door switch. Remove the switch, with a test light check to see if you have power to it. If not you have to trace it to find out why. If you have power, ground it to see if the light will come on. If not check for a good ground. Just my thoughts.