Doing the Prius C is very similar to doing a regular Prius. this is from post #10 Automatic Headlights on the Prius 2010 Accessories Modifications that I used for doing my C post 3 here is write up for the preparing the headlight module. I followed it as written for Part I, Part 2 is little different, so I rewrote it. Part 3 is also revised from the original. I used velcro pieces instead of foam tape. Part 2 the disassembly is part Two, the Prius C is simpler than the regular Prius. Turn the steering wheel all the way to the left, remove the screw that is visible, Turn the steering wheel all the way to the right, remove the screw that is visible. The third screw is located underneath in the middle. Once the screws are out, pry the top and bottom apart. I purchased a set of dash disassembly tools from harbor freight for $5, so that I did not mess things up. Once the bottom is off the connections points are now accessible. Next I pried the dash panel off in the lower left corner above the ODB Connector, this is where installed the module. End of part 2 Part 3 is installation, I made minor revised hawkmoon77â€™s installation steps I connected the power(red) and yellow together and connected them to the grey wire of the power outlet. I connected the black wire and one of the relay lines to a black/white cable I found behind the dash panel area that I removed. I connected the other relay line to pin 19 of http://priuschat.com/forums/attachments/gen-iii-2010-prius-accessories-modifications/16813d1248099406-automatic-headlights-l47.jpg ￼ the Violet wire (12v+Wipers) is connected to the large white wire in the harness under the wiper switch. http://priuschat.com/forums/attachments/gen-iii-2010-prius-accessories-modifications/16814d1248099406-automatic-headlights-l48.jpg ￼ I installed the sensor on the dash next to one that is already there. I used I piece of #12 solid wire to fish the sensor cable down to module, i push the solid wire down from above. then attached the sensor wire and pulled the sensor wires down to the module. Cleaned up the windshield, ton of fingerprints. Tested by turning the car on. the lights came on!, pointed the trouble light at the sensor and they turned off. next I turned the wipers on and the came back on. now you plug cable into the module, that I used velcro to stitch it to the back of the dash panel piece. the relay I velcroed to behind the dash up to left of the panel I removed. Tested by turning the car on. the lights came on!, pointed the trouble light at the sensor and they turned off. next I turned the wipers on and the came back on. Everything should now installed now put the covers back on complete the installation. Thoughts: The pins in two connectors under the steering wheel are very very fragile, I suggest making the attachment to them without disconnecting them. I broke a pin in the headlight one by not being careful about unplugging and replugging the connector. Had to replace it, big pain. installation time should be about 45 minutes if I had to do it again. a very Special Thanks to hawkmoon77 for doing the orginal Prius 2010 auto headlight write up. i include some picture of the underside of steering wheel for reference.