[Technic]

Originally Posted by jaypeeaf

Okay what the hell. I hooked up my Hi/Lo to the Sub right and Sub left with no luck. There's absolutely no sound coming out of my subwoofer. So next I take my sub and hook it up to the Rear Right/Left speakers and this time I do get sound, albiet very faint. So now I know my amp/subwoofer work so I try to go back to Sub right/left. No sound. Next I try Woofer right/left and no luck there either! Out of desperation I hooked up my subwoofer and amp to my neighbors car and get a REAL good WHOMMP out of the sub. Nothing weak like what I got out of the rear left/right. What's going on and why am I getting nothing on my subwoofer channels or very weak at the best? I'm literally frustrated out of my mind at this point.

Here are the two channels that have no sound. Is there something special about BMW Logic7 systems that I'm missing? I hear the sound coming out of the Sub and the Rear woofers while I'm hooked up but can't hear anything across the Sub.

SUB LEFT
Red/White +
Brown/Yellow -
SUB RIGHT
Red/Blue +
Brown/White -

REAR LEFT WOOFER
Yellow/Red +
Yellow/Brown -
REAR RIGHT WOOFER
Blue/Green +
Blue/Brown -

First, don't look for any sub frequencies coming out from the rear woofers, they are crossovered too high for any subwoofer application. That's the reason that the sound is "weak" once the rear speakers outputs are used a sub inputs.

Second, did both Logic7 systems (yours and your neighbor's) are set up the same, as in tone/EQ settings?

It seems to me that your OEM subs are getting no signal at all.