there sort of right...
The trucks factory stereo needs a special wiring harness to get its switched accessory power, because the factory stereo does not require it (and aftermarket decks do) because it recieves its on/off signal through a CAN BUS setup. So, if you installed a aftermarket deck, it wont power up. The special harness fixes this, but its like $50-$75.
You CAN use a standard wiring harness, and run the switched accessory power wire from the aftermarket deck directly to a switched 12v source, like the cigarette lighter 12v line, and then the deck will function correctly.
Thats what I am about to do, I got the standard wiring harness for a buck on ebay (as opposed to the $50-$75 harness), and instead of running the red wire from the deck through the harness (which would be pointless because of the CAN BUS setup, it doesnt bring switched accessory power, so the wire will just be dead in the harness) I am running it directly from the deck to the switched 12v line going to the cig lighter.
I DONT think this will work with a Premium/Nav system, you will need to get the expensive wiring harness from what I understand. With a standard factory system, the kind with no nav and no amp, you should be able to do this trick. Alot of us already have.
They arent lying to you, they just dont really know what there talking about 100%. If you explain this to them though, a good audio shop will be able to do the install with a standard harness, and save you money.
Last edited by MonkeyWrench4000; 05-03-2009 at 10:03 PM.