Brake and Battery lights come for about 5 min after cold start then off

Hello, This is a little strange, but seeing as you are in extreme cold, the parking brake may not be releasing, or it takes 5 minutes to release, and the battery will put out lower voltage when it is cold. You need the factory battery blanket/cover installed, if not there already, and the rear parking brake should be inspected and adjusted if possible. Another possibility is that something is draining your battery while the vehicle is off. Does the truck crank slowly, or does it start spinning like normal when you try to start it?