So I have have this 2012 fit since new, love it and put "leather" Clazio seat covers on it right away. Go them from Bean Garage. Very good service. I had to special order to get the color I wanted so delivery took many weeks. But they told me that, so no surprises.
I also put heater pads on the front seats, two on each and installed a nice dual switch that I got on eBay. All works well but I can't find a power source that shuts off with the ignition.
I have the backlight for the switch and the power for the heater relay all fuse protected and run to one wire. And I have found a good spot in the fuse panel that has power with the key, and turns off a couple of seconds after the key is removed. Then I plug in the new wiring and it stays on. Damnedest thing. It's got me pretty confused.

Where have you guys got power from for seat heaters? I would like to not have to run thru the firewall.
Thanks

 

My pads came with a three way switch. On/low/high. I mounted them on the lower centre panel of the dash and connected then to the Aux outlet. All the wiring is jammed in under the console.

Go here for some pics etc