Front Speakers

Hey guys im having a probleming installing an aftermarket sound system in my friends 03 GA GT. Ok to start of with we replaced everything. Front speakers, Rear speakers, Headunit and put subs in. Ive done this to my GA with no problem but for sum reason when i was finishing up and testing the speakers with the headunit connected only the 6x9s would come on, nothing comes out of the front speakers the only time they will play is when they are wired directly to the Amp. ive tested the speakers with a 9 volt battery and they work fine and ive tried them directly to the amp and it works its just when they ar eon the door they wont play. I think it might be my wires from the Amp to the Harness. Correct me if im wrong but doesnt the speaker wire from the amp for the front door speakers connect to the Harness up front? ive tried everything you guys and cant get these front speakers to come on without directly connecting it to the amp. Please guys any input would be great.

Are you using the factory wirings ??

If you hook another amp up to the exsisting system you can have problems with speakers not working especialy if thiers a factory amp in the driverside trunk.

Not sure on the route of the wires, I thought they all came from the dash wire harness, but could be wired straight from the factory amp.

here is a wire diagram for that......
http://www.the12volt.com/installbay/vehiclewiring/1/yeard/Pontiac.html