Thats some good help there. I have been racking my brain to figure out how to re-create that problem, and you had the solution. Both the phone and Garmin chargers are polarity sensitive, and would blow their fuses under this condition.
An old analog meter would show this miswire problem quickly, but I could see someone with a DMM not noticing / ignoring the reverse polarity indicator and just reading the voltage. (Why would they ignore the polarity indicator? I have many meters, and many probes for them. Often there might be 2 black or two red on the meter, depending on the ends I need. So... often I will have the + probe on the - side, but dont care, the voltage reading is all I am looking for. I could see myself checking the power outlet, finding correct voltage, and not pursuing the polarity of the socket....
)
@JLeTempt - Dick said it was " when picking up our 2018 2552" so either PC factory or was it Campers Inn by then? Dunno.
If you have the ability to verify that indeed that is the problem (miswired power points from radio install) , you might have a little 'pull' with PC to make this a warranty issue that can be resolved locally with a mechanic.
If it is as Dick says, its an assembly error from PC. They may pay for the local Ford dealer to fix it, HOPEFULLY saving you hours of driving. I know thats a bunch of "If's" and "maybe's" but well worth pursuing.
