Jerseyboy64

Hi all. Just purchased a 2006 Grand voyager ltd 2.8 any information appreciated, the rear tail gate is electric but once open closes on its own within seconds, I’ve read a few threads saying it’s the struts but the seller said it’s a sensor, the second problem is the l.h side door, it won’t unlock or open the button on top of the door is down and solid the right hand sliding door works but doesn’t lock any information appreciated as I don’t want to buy the wrong bits