Turn Signal problems of the 2015 GMC Terrain

Vehicle was being driven on rural state highway containing hills and curves to get serviced for low tires. About 20 minutes into drive the seat heater was turned on. About 5 minutes later the radio, speedometer, tachometer, fuel, temperature gauges and turn signals quit working. A tool symbol showed up on the options screen. During the rest of the drive the radio would come on intermittently. At the service center a code scanner showed no codes. The vehicle battery (new) was checked and cables were checked for loose connections and corrosion. The issue continued throughout the service. After service the vehicle was parked for several hours. At startup for the return drive the issue had self corrected and did not return.