Drewzer49a

Hi I’m new to the site and after some help. I have a 2009 E61 and I’m getting a boot open warning even though tailgate and tailgate glass are all shut. Also boot lights remain on. The warning goes when you drive off. I’ve been through all 4 tailgate wiring looms repairing anything that looked suspicious. The tailgate glass microswitch seems to be working ok as does the tailgate soft close. Is there a sensor though in the tailgate power lock mechanism drive motor or any other ideas what the issue could be? Any help appreciated.