The back doors lock up as soon as you shut em, then have to hold unlock from inside and open by exterior handle....and ideas why she'd be doing this?

 

I don't know why.

But....

Over the years, on various cars, I've repaired a few mysterious door lock/door latch problems by giving the latch mechanism a good cleaning-and-lubrication. And the lock rod linkages, too. Remove the door cards and use aerosol brake wash to flood away gunk. After drying use whatever favorite aerosol lube you have on hand.

Also, on a Series III XJ6 at least, the door latches have a tiny spring that can break and bollix things up. You'd have to remove the latch assembly (not that hard) to inspect for this

Cheers
DD

 

Thanks for that