Ford Factory HU & Rear Seat Controls

Hi Everyone,

Help.  What started out to be a simple project is driving me to wits end.  I had some old A/D/S equipment (642CSI & PH15) that had been sitting on the shelf for about 8 years.  Having some time on my hands, I thought I'd do a simple install in my 2000 Ford Excursion - new speakers, (front & rear) and a single 10" sub should do the trick.  Liking the Ford factory HU and changer and not wanting to put too much money into this project, I thought I'd just wire the speaker level outputs from the HU to the 642CSI since it had this ability anyway.

I wired everything up (got the wring codes from Mobile Labs) and hit play.  I was not expecting major SPLs - just a bit better SQ and bass reinforcement compared to the stock system.  What I got was nice highs but anemic midbass and bass.  I checked all of the wiring, the crossover and the amp and everything seemed to be hooked up and operating correctly - in theory anyway, but something was obviously wrong.

I sat in the back seat listening to the system to see if I could figure out what was wrong.  Intending to change the track I was currently listening to, I accidently hit the dual zone system button on the rear seat controls.  All of a sudden I got warm mid bass and decent bass/sub-bass.  The missing SQ and SPLs were found, but what happened.  As near as I can tell, the Ford HU reduces the output to the rear speakers to allow the dual zone system to work.  I'm not sure if this is the reason for my problem or if something else is at play here.  Also, it could be that the 642CSI derrives the low pass signal from the rear speaker inputs, and because of the wonky Ford HU, this results in the poor bass that I'm getting.

I plan to jump the front speaker level outputs to the rear speaker inputs on the crossover to see if this solves the probelm.  If it works then I will lose fader control, but this can be easily fixed on the amp end of things.  If this doesn't work, I'm not sure what my next step will be.  If anyone has had experience with this issue, any help that you could provide would be greatly appreciated.  If not, thank you all for allowing me the opportunity to vent my frustrations!

Regards,

Brian