2020z71

So had to work a short shift this morn. On the way to work as the gauge was getting into the normal area of 200-210 I noticed the gauges dropped to 160. Parked the truck at work and shut off. Fans come on high for a couple of min. After work same thing gauge not working and now Ac isn't blowing cold at all. Everytime I park and shut off the fans come on high.I have to contact the dealer tm morn because of the holiday. Thing thats got me is no check engine light. Nervous to drive as I dont want to overheat the truck now. Any insight to this issue? Thanks