Originally Posted by heavyduty
Connect the red power wire of the FAST-9999 to the constant power wire of the headunit; the blue/white wire of the FAST-9999 to the switched power wire of the headunit of the remote wire of the headunit (not the power antenna wire). Use the front speakers of the harness for your signal source OR you can use the RCA's and plug into the sub-out of the headunit, but DO NOT connect both.
Thanks for the help with this. I did as you said & it's working now. However, I'm concerned about the built-in amp being turned on in my h/u. The H/U built in amp is powering my door & rear speakers and the bta10100 which is already amped. This is a problem, isn't it? I don't have an external amp for my other speakers.