Maybe wires on truck end of 7 pin connector have worked loose. Also there are at least 3 fuses plus a couple of relays under hood that are tow package related.
What type of trailer?
Do trailer lights work properly with other tow vehicles?
06 Titan LE,4x4,Steel Leather,Red Alert,Big Tow,Factory Step Rails,Brush Gaurd,Floor Mat,Bed Extender.. Add On's- In Channel Window Vent,Rear Spoiler mounted on RollBak Retractable bed cover... 2 Deg Timing Mod.. AirRaid TBS... NISMO Cold Air Intake.. BullyDog GT III and FlowMaster cat back dual exhaust.. Drilled/slotted rotors and Evolution pads front and rear.. JBA headers, rear sway bar.