Do mean the USB charging ports? Look at your electrical layout on the unit, all the USB charging ports are typically on one or two fuses but there is several on one fuse. These are cheap charging ports, my unit is less than a year old and already two have died. Remove the screws and pull it out, there should be wire nuts or crimps right behind it. You can check the 12VDC there.
Looking at replacing one with a 120VAC Recept. and the other not sure yet.
More Chinese cheap stuff fails...
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