no heat at feet only in front

Everything works as far as duct operation except for no heat at your feet in front. Heater works for rear passengers in back from under front seats.

 

Both passenger and driver side?
Could be the switch - although if it's toggling between defrost and upper vents not sure why it would neglect lower vents
Blend door actuator - these you can see if you remove the lowest trim panel, on my column shift it's a wraparound panel exposing both driver and passenger sides of the center dash, see if you can see them moving when you move the vent selector, any broken gears etc, I have some spare actuators from a heater box swap I could sell
Blend door actuator wiring - Would have to be tested with multimeter on a "dead actuator" to see if it's recieving the command to move or not. I also have a spare actuator wiring harness but would be a pain to replace with the dash installed
and lastly could be a blend door shaft issue - I had a broken passenger side temp blend door shaft which required replacing the entire heater box assembly, ebay used from a wrecker ~$280 shipped plus AC discharge/recharge and 9 hrs of DIY labor.

 

Seems like I have the same issue Any chance you have pictures or diagrams?