What are the color codes for speaker wires at the speakers The radio wiring colors for a 2003 Ford F-150 XLT are simple to follow and identify. 93 Ford Explorer Stereo Wiring - the12volt 93 Ford Explorer Stereo Wiring. Ford gives you 2 grounds on there stereos. The black is the radio ground and the BLACK/ green is a chassis ground. Never completely figured out why they do this , maybe engine noise issues. I always the BLACK/ green as the ground for my head units. Don't know about the other two.