The harness runs from the door connectors inside the A pillars across under the dash to that box. It appears you have the harness plugged in. If you remove the kick panels under the dash on each side you will probably find the ends that the door cable connectors plug in. The cables on the doors normally have a rubber conduit with the cable bundles inside and the connectors sticking out. Run that through the hole in the A pillar (pillar door hinges are attached to) and plug them in. Add the two circuit breakers and they should work.
The images below are the center you show and the wiring that goes in them. If you note the rear view shows the gray connector as the door and window part, now you just need to find the other end.
Images (Click to enlarge)
Sunday, January 8th, 2017 AT 3:45 PM