Do you remember reading the directions for crate training-housebreaking your dog? If not, do a search on youtube for video directions on how to housebreak your dog. You can also do a google search and read up.
I am assuming your dog is physically mature and healthy.
If it is possible for you to be diligent, and use a take no prisoners approach, housetraining will take you two weeks. You will need a properly sized crate, a leash, a diary, pen, clock, calendar. You and he are in boot camp. Two weeks. Follow the directions. You are starting from scratch. Aside from tornados, earthquakes and massive floods, there are no excuses. Snow and freezing weather is a piece of cake.
Once he is on the schedule (clock, calendar, pen, diary), you will know to look at him at the scheduled moment, and you will see: pacing, dancing, circling, coming to you, going to the door. Take him out out out. Use the leash. Doing so proves to you he went. Don't send him out alone.