The wiring diagram I posted above is for a 2010, and it shows violet w/grey stripe. Have you pulled out your dimmer switch and checked the color of the wire coming out of it?

 

Hey bud.
I did this project a few weeks back.
I pulled the dimmer switch from the dash. Ran hot to the violet wire and ground to a close by bolt.
If you are not getting power it is probably because you have a small censer in the centre of your dash by the windshield. Throw a cloth or something over it and wait 30 seconds. Your LEDs should light up.
I popped mime out and covered it with black electrically tape and pot in back in. This was my lights stay light up at all time. You can dim them down via the switch it them get on you nerves lol.
Hope this helps.

 

I like these little devices. I use it on every electrically project I do. Nice to probe wires without having to cut them. You'll know when ya find the dimmer wire because the inner bulb will dim as you use the dimmer switch.

 

I have checked the dimmer, and no purple with grey stripe, that was 1 reason why I was so confused!
I am fairly certain that I do not have a sensor, but not 100% certain.
When I had my head unit installed, the guy told me I had the upgraded sound system in the truck!
Huh? Those speakers certainly NOT upgrade, and all I had was standard radio, no sync, and no nav!
So, I am still not sure what wire I need

 

Why don't you try checking the voltage of whatever wires you do have coming out of the dimmer, and look for a voltage drop when you dim the lights, like Danasdaddy suggested? That should identify the wire you need. Can you post a picture of the back of your dimmer switch, that shows the wiring?

 

Exactly. Clamp to ground somewhere like a bolt and probe your dimmers wire harness one wire at a time. 1 has to control brightness. If that don't won't let me know and I'll post a pic. of my setup. Might be useful.