sab7860

hi there everyone,anyone please advise, my problem has started with tailgate not closing fully, dealers said proberly lock,so have fitted new lock,still same symptons, tailgate opens fine,tailgate buttons illuminated for 8 seconds or so then go out with interior lights, buttons are totally dead,not working at all, works with key fob,but then only closes 3 quarters,can hear lock mechanism working. also when tailgate is open if I drive down road I get no info on screen telling me that tailgate is open? could it be the pump or sam unit which both are expensive to replace. any advice much appreciated, my friend who is a bit of technician thinks the car does not know that the tailgate is in open position. therefore it think its not open this is why the tailgate buttons are tottaly dead.