no sound, 93 honda prelude si

This maybe a noob problem and I am sure I am overlooking something but i have spent 2 hrs in the Chicago cold and my brain is fried. I have a Alpine CDA-9857. I recently bought a Alpine 12'' Type X SWX-1243D powered by a Hifonics Brutus Bxi2608D Mono Amplifier. The amp has power but i have no sound coming from the sub. This is the first time I have hooked up an amp to this head unit and this also my first time with Hifonics amplifiers. I know the problem must lie in the RCA Cables but I have tried every configuration. Is there somthing I am missing? In the Hifonics manual There is talk of the possibility of needing a RCA Y adaptor. Would that cause no power in the sub? I'm sure this is a easy answer for someone here, and I am sure they are laughing their ass off. Laugh all you want just tell me what I did wrong please. Thank you in advance.

It's a 93 Honda prelude Si First post and I already mess up.

make sure the subwoofer output RCA is turned on in your radio's menu. some have an option to turn it on and off so make sure yours isn't off. you should only need a Y adapter if your radio's subwoofer output is mono and not stereo.

Checked that already. It does have a on/off function for the AUX but it didn't solve my problem.

does it have more than one RCA output? like front or rear? have you tried hooking it to another output just to see because that sub output might just be bad.

It has front rear and sub I tried them all. I am on my way to go get new RCA cables to see if that fixes it.

before you buy new stuff do one last check. make sure the speaker wires from the sub to the amp are wire correctly at the amp. some hifonics amps set up their terminals ++-- not +-+- and if you didn't catch this it can be easy to mess up. just make sure your sub is not wires to both positive terminals

FIXED! Bad RCA cables! Thank you for everyones help!