Originally Posted by merkidemis
As the pad goes between the seat fabric and foam there is very, very, very little risk involved in adding the element, moreso in that there are OEM seats that contain a heated seat element.
Obviously, take extreme care not to knock loose any sensors or pinch any existing wires.
That said, I finished my install today. Pretty straight forward, read the whole how-to here.
For power, my 2012 SE hatchback has existing fuses on the rear fuse panel for heated seats (both are 15A). I simply tapped those for power and ran the wires down under the door sill trim.
I'm happy that you feel like you've accomplished something, but its not quite as safe as you say, at least not per the factory service manual stating that at least for the passenger seat the sensor and the heater pad have to be replaced as a unit and not separately, so that is a potential safety risk you're ignoring. I do hope your pads work better than the factory ones with the cloth fabric because the stock ones seem to have issues and ford hides behind the normal operating characteristic for most flaws on the car.