Hello, I have a 2002 Toyota Sequoia with a JBL 6 CD's , tape deck Radio. What I would like to do is add an amp and subwoofer to the system. The amp will be dedicated to the subwoofer. The problem is the factory radio does not have an rca out for the amp. I would like to keep the Factory radio it works well. So the question is can I hook up the amp for the sub-woofer to my factory radio. I did notice on the back of the radio it has an additional plug for another harness. there is nothing connected at this time to that clip. I was wondering if the clip is an additional out for an amp. TIA