Problem with speaker upgrade-SportTrac w/Pioneer HU

[danlong]

I replaced all 4 door speakers in a friends SportTrac a few days ago, and she has the Pioneer 6 disc HU with the sub behind the seat as well. Also, the front door speakers were the component type sealed units, where as the rears were just normal coaxials. I replaced them all (except the sub) with a set of Pioneer 6x8's that she had from her previous Ex, although now the rear speakers only seem to be about 1/4 as loud as the fronts. I haven't had a chance to tear into it again, but does anyone have any ideas where the problem may be?

 

[mmsdrummer]

In case you didn't check already, check the fade. Otherwise i'm not sure of what else it could be.

 

[danlong]

In case you didn't check already, check the fade. Otherwise i'm not sure of what else it could be.

That has been checked, thanks though.

 

[Alec]

Is there a factory amp still in the mix? I know 98+ most stock HUs had a built in amp, but some still had an external. Maybe the stock speakers were sent different amounts of power because the front were components?

Or maybe there is a bad ground or the polarity is switched?

 

[danlong]

I'm pretty sure the only amp is the sub amp, aside from the HU. Would a polarity switch cause this? The closest wiring diagram I could find was for a 2000 Explorer, but the colors were all the same. I got the diagram from the12volt.com, maybe it was wrong. Here's what they listed:
Left Rear (+) Gray/Light Blue
Left Rear (-) Tan/Yellow
Right Rear (+) Orange/Red
Right Rear (-) Brown/Pink