Passanger side door ajar light wont go off

If you are certain it's the passenger front door, use some penetrant or WD-40 -- and spray right into the door latch area of the door - then open and close the door several times to get the lubricant to penetrate. It could be that the door opening switch on the latch is binding. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops