I need to know if the Infinity system amp in a 2012 JK has separate output and a built in crossover for the top mount tweeters?? Thank You

 

No if I recall, the tweeter is wired from the input side of the amp which leads me to think that it is powered by the HU. There is no crossover just a capacitor on the tweeter to cut off low frequencies.

 

Also please let me know if there is any way to get FULL RANGE to the rear sound bar speakers.....I get great midrange and treble but NO bass of any kind.....I have heard that the factory Infinity system amp cuts out the bass freq. to the sound bar speakers. Any way of getting them back??.....Thanks.....

 

Not with the factory amp. The rear speakers are rear fill. So, I guess they assumed there wasn't any need for great sound in the rear. Sucks, but you're stuck with that on the factory amp.