If the trailer has the one piece 7-prong plug, that is likely your problem. For whatever reason, the integrated controller doesn't like them. Had that same problem on my truck. Chased it for a year. Finally replaced the plug, and the problem went away. Not sure why this happens, but the guy that works on my trailers said it is pretty common.
2012 RAM 3500 Laramie Longhorn DRW CC 4x4 Max Tow, Cummins HO, 60 gallon RDS aux fuel tank, Reese 18k Elite hitch
2003 Dodge Ram 3500 QC SB 4x4 Cummins HO NV5600 with Smarty JR, Jacobs EB (sold)
2002 Gulf Stream Sea Hawk 29FRB with Honda EV6010