Hey everyone. New here but hoping someone can help me. I have a 2003 trailblazer and the heat wont shut off. It does turn off when I turn the vehicle off but anytime the vehicle is running. The heat is on high. I can switch the setting from off to 4 and nothing happens. Just stays on high. Sometimes when switching from 4 to 5 it will go a little higher and you can here a clicking coming from near the blower motor. The resistor has already been replaced and I've tried pulling the hvac fuse for a minute but nothing has improved. Wondering if anyone else has had this problem? What would be best to try next?

 

i know the other day someone posted a "hack" into fixing this issue and it involved putting a ball joint into the heater core line