If I decide to run an extra (-) wire to one of the back speakers (in the
overhead A/C unit), where do the existing wires go from there to the front?
I would assume they follow the A/C connections down the side.  Would this
be a major PITA?  I might consider running 4  larger guage wires if there
was an easier route.  Anyone done this?  By the way, I am sure my '86 was
wired with the common ground, too.

                                                        Jay