An amp is designed to get hot - this is true. But if the amp gets hot the minute the rca's are plugged in then there is a dead short in the system. Do not continue on this path and no number of fans will help you. Disconnect all the speakers and the rca cables. Run a temporary new rca cable over the top of the seats. Connect it to the amp, leave the speakers disconnected. Does the amp turn on and does it get hot. If so then there is a failure inside of the amplifier, more than likely in the output section. Test the speakers to see if they work by using a small AA battery, touch the speaker leads to each terminal of the battery, you should hear the subs snap. If they do not then you might have a blown speaker or a speaker going to ground which would send the amp into protection mode of some sort. Post back the results. To me it sounds either like a rca cable going to ground or a blown amplifier.