Hi, I am the guy that did the Auto-lights on my rav4 2010. Actually, there is nothing for them to do except replace the handle (so instead of "DRL" it says "Auto") and re-program the ECU. I have a 2013 XLE and when I got the car, I researched what it would take.
The light sensor is there, it is there because it NEEDS to dim the head unit screen when it gets dark, otherwise it would be destructing the driver. You can test this by covering the sensor during the day and you will see the screen dim.
The wiring is IDENTICAL to the limited, it uses the green wire for auto-light/DRL option. I know that becouse I first purchased the Limited turn handle and plugged it in, it continued to work as XLE, so I know the wiring is the same. Also the diagram shows green wire from turn handle to ECU as "DRL/Auto-light"
So what controls it is the ECU. On limited it is programmed to do auto-lights, on XLE it is programmed to turn on the DRL. The change they did in 2014 is they use the limited handle and use the same ECU setting. I knew that was coming... 0 cost for Toyota, bump on the price....
I did a mode that is fairly complex on my 2013 rav4, it involves a DEI 545T - auto lights unit, a couple of relays and cutting one wire and splicing into 2 wires. DEI 545T out of the box is a pretty dumb system that directly powers the lights. I did not want to that and also I wanted to be flexible where I can turn it on and off and it wont interfere with default functionality. So when my handle is out of the DRL position it works as factory, when it is in the DRL position the DEI 545T comes on and depending on the light condition it ether runs the DRL or turns on the lights using the factory wiring. The only thing I don't like about DEI 545T is that the light condition change is about 2-3 seconds. I would prefer a 15-30 seconds delay. On a gray day it might turn the lights on and off when passing a big tree or an overpass, otherwise it works fine.
this is not a how-to, more of an idea for a mod.
http://www.rav4world.com/forums/125...xterior/114009-add-auto-lite-option-using-non-oem-equipment-factory-wiring.html