Big Foot Truck Camper NO taillights. Any ideas?

My truck camper tail lights are not working. No break light, no turn signal etc… however…the running lights ALL the way around the camper are all working AOK.

My truck break lights and turn signals are working fine.

Any idea on what would cause ALL camper break/turn signal lights to be off?

Could it be the master power cord running from the camper to the bed of the truck? Possible corrosion or?

Thanks for your help!