aftermarket head unit 03 silverado

Check YELLOW wire on the deck for constant 12 volts and RED wire for switched 12 volts and test BLACK wire for ground. If all these are OK, then check fuse on deck.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

Thanks Jeff!  I found something online about needing to run a switched 12+ wire from the fuse box.  Apparently the radio harness does not provide a switched power source??

Yep, these trucks don't have a switch 12v source.

Got the head unit in, I ran a 12+ wire from the under the dash.  Thanks for the help all, I can not believe GM would not have an switched 12+ from the harness.  Everything should still function correctly witht the way I wired this correct?  Just no door chimes?

With the correct harness you should have no need to run ACC+ power. The correct scosche variant harness is the Lan2SR, which provides ACC+, door chimes, and RAP power. As well as maintaining the data line. Please verify that you have a correct harness. GM did put ACC+ power in their radios, just not in the harness. The reason for this is many vehicles are advancing into single data line functions that do the purpose of 2-10 wires. More cost efficient and saves more weight. If you have it run like you do, you will not have the Retained accessory power (RAP) feature or door chimes. This is sometimes not important to customers. Unfortunately though for the data line, if this is a circular style data, then you could possibly lose vehicle features such as HVAC controls, interior door lighting etc.. Just make sure everything is working properly. Otherwise if it is a star style data line, you are fine.