Audio Systems: trouble with rca cables, rca cables, rca cable

Question
I've been reading for a couple hours now and cannot find a answer to my problem(s) so here i am. well where to start. i have an a alright pioneer deck, (factory door speakers)and then a old school 12" JL w0 with a nice box and some stupid single channel 300 watt amp, and a nice two channel 1000 watt amp, and they both have the l.e.d. troubleshooting light, and well i get green on both of them when i have everything hooked up and nothing whatsoever from my sub, and i use to have it hooked up and everything was gravy, pretty fricken impressive with the 150 rms amp on and yeah it was, but now ive gone through everything three times, all the wire connections are good, all fuses are good, but there seems to be something wrong with my deck or amps, or rca cables, heres what the real deal is, what i found made my sub kick was when i had it on at a low volume and thought i was gunna break it but i pulled out the rca cables on the amp and i noticed a thump from the sub, but it wasnt any ol thump there was beat to it, so i slowly pushed one rca cable end back it and with just the tip barley plugged in it gets mono signal thru!!! so i thought bad rca cable? or back connection so i pulled out my deck and found nothing wrong, so i left it out and  ran to the store got a nice new car audio gold plated monster cable and before running it under carpet and trim - ect. i wanted a dry run, so i hooked it up to my deck from the back and out the car door to my trunk to the amp and well same fucking problem and i ran and bought two other brands at the same store, then went to another store and bought 1 more, but at the end, before i gave up i tried hooking up the other amp at a low volume and i got the same frikken problem whats wrong here? could it be my deck or does god just not want me to bump when im rollin?

Answer
let's back up first. you need a tester. Radio Shack made a cheap little handheld, single speaker amp. You could also use powered computer speakers with an RCA to 3.5mm stereo adaptor.  This way you could test the output of the deck. Yeah it's a pain to set this up, but you have to start somewhere. Let me know what you find.