LS Heating and cooling

I have a lincoln LS 2002 the evaporator discharge temp sensor was bad (code 19 47) and I replaced it. Doing so returned cool air, but now it seems I can't get heat unless the temp is set to highest setting. Also, I get weird temps blowing out as I drive. Sometimes all cold, other times I get a decent mix of hot and cold. I've gotten cold out drivers side and full hot out of passenger side with only a 5 degree difference. Thinking I need to replace the dvvc, but would like to verify before buying a new part if possible. Any help on how to determine if the dvvc is bad?

Any help is appreciated.