stereo wiring in 93 ford areostar

I am trying to install an aftermarket stereo in a 93 ford areostar with the factory rear radio control and am having troubles getting the speaker wires figured out. I can either get one front and one rear or both front or both rear speakers to work together but I can't get all four to work together. Any help with this would be much appreciated.

If your van has the headphone jack behind the drivers seat, you need to run new speaker wire to that location and catch the speakers there. 

Your van may also be common ground which means you will have to run new speaker wire to each speacker

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Do it right the first time

if the van is common ground you don't necessarily need to run new speaker wire.  You can get a floating ground adaptor from scosche for about $13 or build one yourself for about $5.  This will utilize your factory wiring so all the wires you have to catch are right behind the radio.

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