Ford Repair: Rear speakers on Expy, rear speakers, expy

Question
I have a 1999 Expedition EB.  Ever since I owned it, the only speakers that seem to work are the front.  The ones in the rear do not work (other than the subwoofer all the way in the back.) My particular Expy has a "dummy" console where the rear speakers are suppose to be able to be controlled for the middle row in the back of the center console. There is a plug just dangling inside that was suppose to plug into the PC board for the controls (which is not there). In my book it says to give control to the rear speakers to hold down the presets 3 & 5 - which does nothing - I assume because there is no rear controller hooked up. I am wondering if someone has removed it before I bought it, and when it was hooked up, the rear speakers were set to mute because the middle row was using the headphones.  Is there a way for me to "Fool" the system to get them working again? Will I need to find a control board to hook it back up?  Where would I find one?  Any help would be great - thanks!

Answer
All I see listed in the manuals is premium sound, or super sound. Either one requires a rear integrated control panel, amplifier, and subwoofer.

Perhaps who ever had the vehicle before you had modified the system. I can't see removing the rear panel, what reason would there be for that? Unless this unit was misbuilt originally and no one noticed?

I suppose at a minimum you would need the rear panel just to find out if the rear works. How about a wrecking yard or dismantler? Might be able to find a used one, I think they were all black, unless you need the cover trim.

Let me know how it goes.