I was searching the Internet for a hint to where the blend door actuator is located on my heater. I had to register to view the photos posted by "03Huggy". Two thumbs up for his explaining them. I don't have a Blazer but have an S-10 PK-in the family. This site has been the most help I found after hours of looking for clues. I bit the bullet this afternoon and I will post a separate "technical" posting to explain the "different" :duh: problem I found that might help others.