Rear door open message and door won't lock; window doesn't work

[Cornishgirl]

I have an error message that rear passenger door is open when it isn't. Also their appears to be no electricity getting to door as it won't lock and window doesn't work.

What part might I need? My dealer doesn't keep parts in stock and I will have to go back twice which is two long trips. I was thinking I could buy the most likely parts and bring them with me.

Any ideas?