This is where the service manual is your friend. You can locate the schematics for the various door circuits and see if any of the wires are hot. I expect there are none.

If that is the case, you have to investigate whether or not the duct from the body to the door is hollow and just a path for wires or if there is an actual bulkhead seal that the existing wires pass through.

Also, sometimes, even if there is a true bulkhead seal, the factory may have an extra wire or two that are not used... you only need one as there are grounds everywhere.

Good luck!