The contact owns a 2016 Ram 1500. The contact stated while driving at approximately 40 MPH, he heard the sound of the tailgate opening independently. When the contact stopped the vehicle, he observed that the tailgate was open and he was able to raise and secure the tailgate. The contact stated that later he was starting the vehicle and saw that the tailgate was again open, however, he was not able to secure the tailgate. The contact stated no warning light was illuminated. The contact had not taken the vehicle to a local dealer or independent mechanic. The vehicle was not diagnosed and was not repaired. The contact called a local dealer and was informed that he would need to bring the vehicle in for a diagnostic check. The contact asked if there was an open recall. The contact was advised by the dealer that NHTSA Campaign Number: 18V486000 (Structure, Latches/Locks/Linkages) had been completed on the vehicle by a previous owner and he was no longer covered by the recall. The manufacturer was not informed of the failure. The failure mileage was approximately 78,000.