Heater not hot

First day of cold weather so I adjusted the temperature to around 90 degrees to get the cold out of the truck. I dive about 45 miles to work and the whole way, it blew cold air. While the temperature outside was in the teens, my outside reading in the truck was 40 degrees. Replaced the outside air temperature sensor. Next day, same issue but my outside air temperature was closer to reality. Next I noticed that my temperature gauge was not getting off 'C', maybe a bit, but no where close to mid range. I replace the thermostat with a 195 degree OEM part. Now I get lukewarm air, but not hot.

Any help would be great.