01 mustang radio

doing a radio install on an 01 mustang with the mach 460 sound system, i have the correct harness for this particular sound system to add an aftermarket HU the head unit only has on pair of pre-outs and the harness for this car has rca jacks on it to power the factory amps, but also needed another pair of pre outs to hook up the aftermarket amp/sub, so i used y-splitter cables and got it all hooked up, but now the subs are not hitting at all like they did before witht the stock head unit.  What is the problem?? ive set all the settings on the radio like they need to be and have the amp up enough and the sub setting on the radio up enough, its like the sub is getting a high pass signalmustang GT convertible with lots of performance mods... Alpine M500 amp with sealed enclosure, 10 inch kappa perfect, clarion cz500 head unit, kicker ks speakers all around

the radio is a jvc KD-R300 and only has one set of pre-outs but it can be rear or selectable sub out so maybe thats why its not working b/c im using y-splitters to hook up the factory amp rca's as well as the aftermarket rca's to power amp/submustang GT convertible with lots of performance mods... Alpine M500 amp with sealed enclosure, 10 inch kappa perfect, clarion cz500 head unit, kicker ks speakers all around

use a line output converter for the wire harness and use the JVC sub out

ah yeah, well i had a line out converter already hooked to the back speakers for the amp/sub when i had the factory radio b/c i couldnt get a low pass signal behind the radio anywhere so am i gona have to get some kind of 17 foot  extension rca cable with male on one end and female on the other so i can run it back to the rear speaker again for the factory rca wire harness deal?mustang GT convertible with lots of performance mods... Alpine M500 amp with sealed enclosure, 10 inch kappa perfect, clarion cz500 head unit, kicker ks speakers all around

no, you will need a longer set of RCAs to reach the sub amp from the back of the radio and move the LOC to behind the radio for the harness to use. hook it up to the JVC's speaker wires, that way, you will still have control over the sound from the jvc before it goes into the factory amp.

ok i just tryed that, but still was not getting any bass, im not sure why, b/c the radio has a sub level control but its just not getting the right signal so i just hooked it back to the LOC at the rear speakers and it works fine now, but thanks for the inputmustang GT convertible with lots of performance mods... Alpine M500 amp with sealed enclosure, 10 inch kappa perfect, clarion cz500 head unit, kicker ks speakers all around

you didn't get any bass with the amp hooked to the sub output of the radio? that doesn't make sense, but whatever works for you