blowing only hot air, can not turn H/A off but don't hear a motor running

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! Your Blazer is full of hot air and who likes that? Not me or you in the summertime that's who! There may be an issue with the blend door actuator or the HVAC controls. The blend door actuator controls the direction of airflow and temperature inside the vehicle. If it's malfunctioning, it could be stuck in the hot air position, preventing you from turning off the heat and that's not cool. Additionally, the HVAC controls might be faulty, preventing you from controlling the temperature. I recommend having a mechanic inspect the blend door actuator and HVAC controls to diagnose and repair the issue as you may not want to dig into the dash. If you have any other questions feel free to call us at 877-913-1554! We'll gladly find you a certified RepairPal shop in your area!