Can't help on the complexity but you're sure it's a motor problem rather than a wiring problem? Wiring to the tailgate can get damaged fairly easily and/or has poorly designed routing.
Yes I was going to get it fixed earlier this year and the garage said that it was the motor that had gone. I have taken a quick look (a very quick look) and as I am not the most gifted of mechanics I will probably get the garage to fit it.
