Looking for help with wiring diagrams for BA OEM factory stereo. My factory amp works w stock head unit but not aftermarket. I believe the factory amp is not turning on because there is another wiring harness that normally hooks up to stock stereo but not to the wiring harness for an aftermarket head unit. Looking at the second small harness it says amp right on it in small letters...just as the other harness has written on it for the speaker wires going to amp. I think this little problem has caused a lot of issues for a lot of people...thinking the factory amp was bad and needing to be replaced and so on... Thanks.