2010 door Wiring harness swap?

Hey guys, Hopefully this is in the right forum, please move if not.

So My dad and I went to swap out the door on my 2010 VW beetle to discover the door we got from the salvage yard has a TOTALLY different wiring harness. My original door has a three prong, and the new door has a two.

I am clueless in this department, we fought for a good hour just trying to disconnect the entire harness and we finally gave up. Each harness begins with 8 wires and we decided to splice them together. Problem solved? Not quite. ONE wire is different on these harnesses. My dad is a retired electrician and said he can splice all the other wires but that one on each end. I'm concerned as to what will not work properly and if we can just splice those two wires together anyways.

Does anyone have any insight as to what the difference is in the harnesses and what they control? Anyone ever spliced an old two prong into a three prong?

(I hope I made sense here.) :|