I'm going to try and help a friend swap out his doors on his '81 300SE. The doors were removed from a '81 300SD. My question is about the wiring. The wires have been cut on the replacement doors(actually replacing both on drivers side). Is this simply a matter of trying to remove all wires from the replacement doors and trying to reroute the existing wires? Any tips or tricks?

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1995 E420 152k
1991 300D 2.5 348116 daily driver
1992 300E 2.6 196k-work in progress(head gasket)
2002 BMW 745Li 93k