need some help...

[Rollie396]

I'm installing a new unit (on the cheap) in my 80.The head unit is a new 4x45 cheapo (with aux jack which is the whole reason I'm doing this).I bought a pair of 5" sony speakers to use on the front channels and am using an old Clarion 10" sub and Alpine 160 watt(?) amp that I've had forever.
I wired everything up going by the instructions provided with the deck and stuff I pulled off the net for the amp.I intended to run the fronts off deck power and sub off the amp by bridging the channels.It's just temporary right now as I wanted to make sure things work...which they don't of course.The amp and sub work just fine,but I can't get the front channels to work.I tested the speakers and they seem fine.I hooked up the craptabulous rear speakers to both the front channels and rear but got nothing.I'm pretty sure my ground is good.It's hooked to the ground block on the a pillar on the driver side under the dash.It doesn't matter if I play with the fader,balance,turn the sub on or off,unhook the sub/amp.Unless I turn the sub off,it always plays but nothing through the other speakers.
Oh and I've double and triple checked my wiring of the speakers and I'm sure it's correct.Help/advice/ideas would be great!