Take the rear panel off and you'll find a small silver lever in the white plastic area. Push down with a screw driver and it will open. You will find the wires inside the rubber sleeve between the body and door is full of bare wires. There is a splice kit available but from Latvia on ebay for 30 bucks. Good luck. Remember to cuss fiat for using cheap wiring. :)
Actually didn’t have to spend 15mins trying to pry open, there’s a manual release right on the white plastic part of the mechanism on the inside of the hatch.