Rear speakers and amplifier/sub not working

[Whalin]

I just bought a 2004 expedition Eddie Bauer that already had a newer double din head unit installed in it but the rear door speakers, sub and amplifier aren't working. I’ve installed every after market head unit in each vehicle I’ve owned over the years and have never run into a problem as common as this in the expedition from what I’ve read up on. Has anyone has this issue and If so what was the fix/problem you had found. I’ve done some trouble shooting to the wiring and HU itself and everything is seeming to be fine. My next test is just gonna be taking out the HU that’s in there and pop in my old one I had in my 92 bronco and see what comes of that. Hopefully I get a get tips or answers to the issue before I start dismantling the dash asked center console again to further the trouble shooting of it. Thanks all for any info… Happy Expeditions to ya

 

[cilynx]

I'm not sure if the earlier gens work the same way, but I'm playing with something similar on my 2015. In my truck, the rear speaker connection from the head doesn't actually go anywhere. The front speaker lines go back to the amp/dsp and the amp/dsp splits that single stereo signal out to the fronts, rear doors, rear pillars, and the sub. A lot of the new fancy head units are connected to HS-CAN for fancy stuff like door open displays and A/C controls, but they're not connected to the I-CAN bus that the amp/dsp is on. One potential workaround is to put the OEM head back, make sure everything works, set your fade, balance, and eq where you want them and set your volume to 90% or so. After that, you can swap the aftermarket head in and the amp should remember the settings and generally work.

Keep in mind that whoever installed the aftermarket head could have done something annoying like not using the factory wiring harness and just running a couple new lines to the front doors because those are easy and ignoring everything else because everything else is hard.

 

[jrosby]

Hope this message reaches you guys! I've looked at the wiring for 2010 Expedition as I am having a similar issue. According to the wiring diagram the factory amplifier must be "Enabled" in order for the sound from RSE to be processed. I'm not sure how to get that to happen. I don't know if I need to supply power or a low voltage signal or what. If anyone out there can help please, o-please do so LOL!