I bought a new stereo(pioneer) from Crutchfield a few months ago. What I recently noticed is the sub woofers behind the seats are not working. They do work with the original stereo so there is no issue with them. I recently changed the harness again as per their instructions. The phono jacks front and rear work only on the front. So my guess is there is a common wire that is not receiving a signal but I can not seem to figure it out. I would like some ideas or instructions in what is wrong and a remedy. Crutchfield rep was helpful but they are missing something also.

thanks

 

I have the exact same issue with my Alpine unit. It probably means we'll be swapping out the factory amp next...

 

I have the Alpine IDX-001 installed, it has never been real good with the subs ...
But I keep it cause I LOVE the retro 60's clock display

( picture from the web, not mine )

 

Your new head unit is probably wired into only two of the six inputs to the amplifier. One right and left pair is for the doors. Each subwoofer has two voice coils and takes two channels of the amplifier. See this old post for details: https://www.crossfireforum.org/forum/audio-video-electronics/35585-new-radio-install-labeled-amp-diagram.html