Ok heres my problem, hope you guys can help. I have a cobalt ss with the pioneer 7 speaker with sub. We got done putting new speakers in a new mb quarts 1500d mono block amp and 1 kicker L7. Everything seems to be wired correctly unit works fine and amp turns on when car is on and off when car is off. The problem is my sub isnt loud at all, actually you cant tell its running unless you fade the speakers out. I dont know if we hooked it up wrong or not but from the head unit we put the RCA from the swl and swr then routed them to the r and l speaker inputs on the amp.

We do know the sub works and i just got the amp tested today and they said it was also good. So now i am just confussed on how to get it to work i did turn on the sub in the menu in the avic and messed with the bass boost but nothing seemed to work out. Me and my friend were told that since im running one sub i had to use a y splitter. Dont know what to do electricity is not my strong point, so any help would be greatly appreceated. Lastly the stock sub in the car does work, does it have to be spliced there or anything of that sort?

1st re-check that the sub is "ON" in the head unit.

2nd check the gain on the amp.

3rd, I don't understand how you went from the sub RCA cables to speaker inputs on the amp. Do you mean you went to the RCA inputs of the amp, or that you went to speaker level inputs on the amp? If the latter, then that may well the amp is expecting a much larger signal. Run RCA to RCA.

You could try moving the SWR/SWL RCA cables over to the rear speaker output RCA cables (make sure the sound isn't faded all the way forward) - if it works then it's in the head unit, if it doesn't then you still have some sort of wiring issue (usually a bad ground to the amp).