Car Stereos: Locating wires, rear cargo area, trailblazer ext

Question
I want to install an amp to my 03 trailblazer ext. Which color are the rear speaker wires on the stock 6 disc stereo so I can connect my RCA module.Also I want to connect a iPhone to my radio thru the earbud Jack on the phone so how could I find the wiring for the aux button on the stock stereo. Any help would be appreciated thanx!!!

Answer
Hi Ralph,

To answer your question, I'd need to know whether your Trailblazer is equipped with a Bose factory sound system, and whether it has rear seat audio controls.  If you have the Bose system, you won't find any useful wires at the back of the head unit; you'd need to do your wiring at the factory amplifier in the rear cargo area (or at the speaker wires in the B-pillars).  Non-Bose vehicles should have speaker wires behind the radio, though.

If you want to connect your iPhone as an auxiliary source, you won't be able to just tap into the stock auxiliary plug wires.  You'll need to use an OEM adapter module, like PAC's AAI-GM12.

Usually, the GM wire colors for the rear speakers are brown (+) and yellow (-) on the left, and dark blue (+) and light blue (-) on the right.  In your vehicle, the left positive wire may be brown/white at the radio, and the negative wire colors may be different depending on whether you have the rear seat audio controls.

Hope this helps!

Brian