Car Stereos: grand cherokee radio problems, speaker level signal, factory speakers

Question
hello good day,

here is the scenario, months ago i wanted to upgrade the HU in my GC but couldnt becuase of the PCI Bus cable on the back of the stock HU. forward to now. i have added an amp and subs to my stock HU (havent heard them sound yet) my question, i bought a lineout converter and installed it in my jeep, now i assume everything is correctly wired up (to the rear speakers). but i dont have any sound coming to the subs. there is power to the amp becuase the amp power's on. is there any way i can check to see if everything is working correctly on the line out converter? could i have a defective amp even if it turns on? this is all frustrating all i want is some bass in my car thats it...your help will greatly be appreciated thank you in advance for your help

Answer
Ariel, Sounds like a good addition.  I am sure it is just a wiring issue.  When wiring your amplifier, it is best to splice into the rear speaker wires close to the rear speakers.  That way you know you will have a definite speaker level signal.  After securing that signal, you know your line-level converter has a good signal to work with.  If you do not want to relocate where you are spliced into speaker wires, then just find an old speaker somewhere, and hook it up to that lead.  It should sound fairly loud like one of your factory speakers.  Then, you are sure your converter has a good input signal.  Then, you want to double check your power and ground connections.  The power wires should both have power through them when the system is supposed to be on.  The ground wire should be as short as possible and connected securely to a metal body part.  I think once your connections are all checked and correct, your amp should work fine.  If it is not working after the wiring check, I would take the line-level converter to your local stereo shop, and have them test it for you.  That will tell you whether your problem lies in the converter or the amplifier.  Hope this helps, Scott