2008 Chevy Silverado WT - Cruse Control

Just began noticing a problem with the Cruse Control on my company truck . It seems the Cruse Control will not function in the morning , when everything is cold . Latter on , when the interior warms up , it will start working & will continue to do so , for the remainder of the day . My first guess is that the fault is in the controls on the steering wheel ? Anyone having a pdf of the wiring diagram for the Cruse Control , I would be grateful . Thanks , :-) Wyr God bless