i have a 2013 xc70. For the second time the tailgate has failed. It won't open, and none of the other functions work. Tha fault display on my dashboard tell me it's open and the brake light flash manically when I brake. I have pried off the top of the trim and sprayed some wd40 onto the mechanism but I can see no moving parts. This worked once but does not work now. Is there a manual way of opening it (there is no keyhole hidden or otherwise in the tail gate) and is there a fix short of taking it to the main dealer? (Which I had to do last time)