2017 western star

Truck is brand new. 8000 miles. The power to the rear mophet plug cut out for the reverse lights and alarm. checked all the fuses and nothing. checked for power to mophet and it's all there except for what i need with reverse. checked the harness and nothing seems wrong. the truck is a 2017 so i dont want to start ripping up the harness but if i have to i have to. anyone have some imput? it don't know the model but its a flatbed.

Ran a volt meter across the plug. 0 power when all lights are off and in reverse. :' (


Edit: Truck has everything working besides this one power reley. the reverse lights work on the truck. and the alarm.