Brenty D

I have a 2016 Sierra with the exact same issue and have had the issue since new. It works good 95% of the time. I told the dealer about it when it was new but it never acted up when i was at the dealer so they did nothing about it. The only way i have found that resolves the issue temporarily is to turn off the truck, wait for all accessory lights to turn off than restart the truck and it always works after that. seems like its usually first thing in the morning when starting it and i had a new battery installed not that long ago but its almost like when the vehicle charges up the battery ever so little it works better. I'm assuming its a sticky relay that needs optimal volts to operate correctly.