InfoAudio01

Unfortinately for car audio there is not just one answer for this type of problem. Rca's can definetly throw the amp into protection if it is cut, pinched, or simply grounding out against a sharp piece of metal in your vehicle.

try unplugging the rcas only and turn on your amp and run idle for awhile. if your amp stays in the normal operating stage then simply pull the deck from the dash and run a pair of rcas from your Head Unit over your seats directly to the amp to save some time and this allows you to know for sure that the cables are not grounding out. problem solved? now run the new rcas.

for grounding issues....get ahold of a multimeter. turn it on to DC Voltage and ground the black probe to the ground at the amp and then connect the red probe to the power wire at the amp...now have a friend turn the volume up to a loud listening volume. if the voltage displayed on the meter drops a reasonable amount then you have a bad ground.

other issues can be the case here but this is a good starting point that only takes a few minutes to test and can save you the hassle of taking it into a shop, which may charge you for their time.

if this still doesnt open up any ideas, post back and I can further assist.