[lisounds]

Since you stated that you have a full aftermarket sound system then this is what you must check:

pioneer:
Red---- 12 volt switched on/off with key
Yellow--12 volt constant power / battery keeps memory and clock
Black.... ground

at amp:

power... from battery 12 volt usually a thick wire 8 or 4 gauge with aftermarket fuse by battery
ground .. to solid unpainted metal same size thickness wire as power
REM.... remote or turn on ( this wire comes from back of head unit ( blue with white trace) will be 12 volt power on/ off with radio power.

if for some reason the blue /white wire from the radio does not respond to power on/off with radio..than you can connect it to the red behind radio ...just make sure it cuts off with key out of ignition

** make sure rca cables are plugged in correct position on amp and radio.

** also use a meter to test wire. i have see glass fuses that light up a test light but do not deliver 12-14 volts with car running.