Guillermo Munoz, unfortunately there is no way to get inside the door. The insulation is sprayed in after all the wires, water lines etc… are in place. This insulation pushes all the air out so the door won’t sweat. Awhile back, I was curious about what was inside a door, so I took an old door apart. I had to cut the liner off with a filet knife. The insulation is very porous, kind of like chalk. It is in every crack and crevice. The wires were hard to find. Once I found them, I couldn’t pull them free. I had to cut them out. Same with the water line. It made a mess
I’ve never had a wire break inside the top of the door. If you can get enough slack to repair it, you’ll need to buy a new door.