need wiring harness help please

[Speed-Techniques]

I have a 90 hatch, the window mechanism broke... It WAS manual.I took my parts car's power door all apart, and frankensteined all the parts into the manual door, with broken stuff (all removed and switched over...) Well that was hard, but doable. Unfortunately, I assumed there would be an empty plug waiting for the new power accessories... there is not. I looked at taking the harness out of my power parts car but jesus that's gonna be hard... does anyone know if I can just cut into the existing large harness that runs under the dash ? Does anyone have that harness piece already out of the car ? thanks for any help !! Luke