I had a Kenwood KDC-X995 installed today and I'm not too sure that they hooked it up properly. It sounds better than the OEM radio but that said it seems to me like all the bass is coming out the door speakers rather than the subs. If I go to the menu on the Kenwood and turn the sub on & off it makes no difference. Changing the sub level also makes no difference. I thought maybe they ran the "rear" output from the HU to the amp but when I crank the fader all the way to the rear the sound dies out so that's not the case.

How can I determine if it is wired wrong and how should it have been wired?

Never mind guys - I didn't do my homework. After a more through search of this forum I now know what I need to do to get the subs working properly. Sorry for the bother.,