V70/(855) Tailgate wiring harness

Hi all,
I need some advice about replacing our V70 (2000) tailgate wiring
harness. I think one or more wires is broken in the harness where it
twists near the hinge because the unlocking motor only works when the
tailgate is lifted clear up or most of the way up.

My questions are,

1. Is threading a new harness something I can do without removing
the gate itself?
2. How do you get the cable ends through the small round holes
in the door frame and the hinge? Do the connectors come off
some how or what?
3. Which end of the harness should I try and thread through?


Any ideas and/references would really be appreciated.

Thanks, Brad