Sub on GM factory radio

I would hook up sub on my factory radio. Is there a Amp turn on wire on the radio.

I ask because they make factory amp & sub for this truck.

Or I will have hook up a switch in relays to ing wire.

In what are the rear Spekers wires colors.

Thank you.

First off, the GM factory radio does not have an amp turn on.  Just tap into any ignition (turn on) wire you can find.  Just get a test light and find one that turns on with the car.  As for the colors of the speaker wires, I'm not really sure so you'd have to figure that one out yourself.

Try popping the speakers..

-Take a 9V battery and connect a wire to the positive and to the negative terminals

-Connect these wires to random cables coming off of the stereo (try wires of the same color, one with a stripe and one without).

-When you have a pair of speaker cables, the corresponding speaker will make a noise, or "pop"

This is the long way to find the speaker cables.

my god man... did you just suggest someone probe for voltage with a TESTLIGHT?   i would change that to say "Just get a DVM and find one that turns on with the car."

The Truck is a 2003 gmc yukon. I just a ask about the amp turn on because some of 2003 gmc yukon have amp with sub in them.

I know not to use a test light I use a prob to test my wire. I wouldn't  get the ign @ the fuse box. I get it under dash where I can put a inline fuse on it just in case.  Seven years ago  doing  my Circuit City days I seen some brun up fuse box come into the road shop. Thank you guys for all the help.