The goal: have a 12v source of power in the bed of the pickup. This would be used to power a 120 volt compressor via a 400 watt invertor.
Needed hardware: besides the inverter, a trailer plug with a 6-8 ft power cord would be made using 12 ga stranded wire. Ring terminals would be applied to the ends of the wires.
The question: Would the Black (+) and white ground (-) be available and supply 12 volts through the 7-way connector?