Having a problem with the tailgate latch. Wasn't a problem until I opened it for the 1st time(bought the X used with 155000 miles), now when I close the gate, the door ajar light is on in the dash, it is closed but I can pull the gate & it moves abouy 1/4 inch or so but won't open. Assuming it's the latch in the gate not working correctly. Sprayed the latch with PB blaster but didn't help. Do I need to replace the latch? Looks pretty simple to do, how much $$ would part be at dealer? Or is this a common problem with an easy trick fix? Thanks for any advice