Heat on passenger side cool/cold on driver side?

I replaced this and it did not solve the problem. Looks to me like there is another door that is stuck. Possibly floor vent door. Is there a vacuum control valve for this?

I need to know where #24 is located.

This door / flap does not move in any control position, heat, A/C, vent, defrost. There is plenty of hot air behind it, but it can't get past it. What is this door and should it be controlled somehow. It's at the very bottom of the HVAC, floor heat comes out of this opening.

Thanks Ken, all the vacuum actuators are working, and they push or pull the levers they are hooked up to. Then blend door servo did help, but now
I'm off on a tangent here, looking into why this truck does not have good heat.
I can't find any lever or way that door can be moved with an actuator. It's spring loaded and I can push it with my finger, but I see nothing sticking out the side of the housing that would connect to an actuator. Any diagrams or help will be appreciated.

The door i'm talking about is under the blend door, in front of the heater core. I believe the door opens to allow air to pass through the heater core. When the door is closed air passes over the heater core.

Hi Ken, I took your advice and read this guide. I bought a cooling system flush and also used a hose to flush out the core. Looking over the entire system it seems I am retracing the previous owners attempt to resolve the lame heating. I see there is a newer water pump, thermostat housing and a new small hose. Also, the blend door actuator I took out was the same aftermarket actuator I bought and installed. I'm still wondering about the spring-loaded door in the front of the heater case. I have not been able to find any pictures or diagrams showing it. The temperature gauge on the dash reads normal.
Any other ideas?

When I changed the blend door actuator I was able to move the door back and forth by hand using the old actuator arm from the old unit.

Ken,

Thanks for the advice, I've been looking at YouTube videos and digging around under the dash and found the problem. I found the air recirculate door fell off the arm and was laying on top of the fan. This blocked most of the air flow through the system. I just removed it, not sure I need to put it back in place. For now, i'm just going to gorilla tape over the recirculate intake vent side so the outside air can't come straight in behind the glove box. I hope this will solve the issues.

Thanks again

Hi Ken, thanks for all the great advice. Still, something not right. Do you have any information on where the defrost vacuum actuator is located on the driver's side? I'm trying to trace where the yellow vacuum line goes from the HVAC door mode selector.