I have a 99' quad cab w/ the infinity system. Does anyone know what color wires off of the back of the stock stereo are for the rear speakers. I want to T-tap off these wires for a line converter for my amp. Please reply, thanks!

 

Speaker signal and 12v power run to the amps mounted on the front door speakers. The amps feed the front and rear door speakers. The signal from the head unit is pre-amp only, won't power a speaker properly.

 

The amps mounted on the front speakers also power the rear speakers? Where would be the best place to tap off to hook up a amp? The signal off the head unit supplied with a amp is not enough power for a 12" sub?

 

Yes.
Tap the speaker signal at the head unit to feed an amp, but the unit may not have enough signal to feed your new amp and the two existing amps.
Don't know. Try it.

 

OK, The stock head unit puts out crap power and is probably already maxed out. Everyone I talked to said to loose the head unit. I'm trying to keep my truck as stock as possible. Just want a liitle bass to fill up the very weak sound the infinity system puts out! Thanks for the help, I guess I'll just try it.