So I have searched and read through a couple of these posts related to no heat on the floor setting of these Blazers (2000 LT 4 door in my case). I pulled off the black plastic panels that have a couple screws mounting them above the drivers side foot well. I can see both actuators above the gas pedal but the lower one that has the red and blue lines going to it seems to do nothing. My heat/cool air will blow correctly on all settings except floor. When I switch it to floor I think it just goes to defrost and the floor doesn't open period. I dont hear any hissing, and I haven't checked the tee above the brake booster yet (I will check it tonight). When I have the truck running and I pull the red and blue hoses off the actuator I don't hear or feel any vacuum. The white plastic linkage doesn't appear to be broken and I'm not sure if the actuator will move in and out or not. I didn't push it to hard with my hand in fear of possibly breaking something and causing more problems. I've only had this vehicle about a month and this seems to be the only aggravating problem so far.. when its cold out. Any help or direction would be grand.