I just got through installing the d3 in a 04 sierra and the d3 won't turn on. There is no noise or lights I used a volt meter and is getting power but won't turn on. Any suggestions?

Well, the stupid part first. Did you turn the car on?

Anyway. Make sure the accessory wire is hooked up the the switched power wire properly. It may have come loose in the installation.

Also check your fuse(s) and make sure none are blown.

If the constant power wire and accessory (switched) power wire are hooked up properly, the fuse(s) aren't blown, and the ignition is turned on, the unit should power up.

If not, there's probably something wrong with the unit. Asuming the power wires going to the radio aren't shorted out or something.

if you didnt use the gmos05 from metra or the ncgm39b from ai you prob dont have acc power if you did then do what he said

Ok so i went to the audio store and they told me gm didnt have an accessory wire to the radio and that i would have to tap into a switched wire on the fuse block. So which wire could i use that is switched and are there any wires I could use closer to the radio? There are so many wires i dont want to cut into all of them to find a switched one. Thanks for the help guys.

use a fuse and tap into the orange or brown ignition wire from the steering culumn. dont tap fuses its the very last resort