Sounds like you have DC power then, my unit is not here so I can not look at it to help, can you see the DC control panel wiring when you open the outside cover, if so I'd look to a lose connection? Did this work prior, at PDI, are the lights on above the frig door (orange) on the control panel?
2011 GMC 3500HD 4x4 Crew DRW Duramax
2012 Sierra 365SAQ
2006 Police Roadking FLHPi