2004 chevy silverado wiring diagram

I have searched the internet up and down... as well as this forum to possibly find the answer to my question, but the only luck i have had is to pay a ridiculous amount of money for the question to be answered.  I chose option B... and here it is.

I bought a Plasmaglow Firestorm tailgate bar.  In order to function, it needs to be hardwired into the truck.  The only thing the directions say is to wire the six wires to different leads, but does not say how to find them.

Does anyone know where i can get the wiring diagram for a 2004 Chevy Silverado without having to pay an arm and a leg?  Specifically, all i need is the rear wiring harness and which colored wires do what.

If someone is thinking outside the box and has a better idea... please enlighten me!

Thanks!

So what connections do you need? This lightbar is basically a tail lights, and brake lights....right?

Asking for info on "the rear wire harness" is open ended and vague. WHAT rear harness?  Can you be specific in your needs?

Does the truck have a tow package, that would include all the connections for trailer light's.

Sorry... when i refer to the rear wire harness... i am talking about the harness that contains all the wires for the rear lights (brake, turn, trailer, lic plate, etc), before it splits off into the direct components (right brake light, left brake light, etc). 

As for the lightbar, It has six wires for three colors and needs to be connected to the brake lights, right turn signal, left turn signal, and reverse lights.  The other two wires are for the positive and negative connections.

My truck does have a tow package, but this specific light bar needs to be hardwired into the truck (which means i have to splice into the wiring), i can't just plug it into the tow package like most of the light bars out there.

I appreciate your help... if i did not get specific enough, please let me know, and i'll go take a picture of the location i am thinking of splicing into.  My only dilemma is figuring out which wire goes where.

If your truck has the tow package, simply splice into the wiring behind the trailer connector.  Most chevy trucks I have seen have a tag on the harness to the trailer plug that identifies the wire colors and function.  There may, in fact be a second set of wires bundled up at the front left corner of the bed which would be used for a second trailer plug in the bed (for a 5th wheel trailer).  You could use that as well.