The best way to prevent anything falling through is to make sure that they are closed. If your child is playing around them then make sure that they are closed.
in the floor.
Yes vents can be in the floor instead of the wall.
on the floor on the floor
should be on floor.
the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
There are heater doors on the heat blower box that direct the path of the heat. Apparently the heater door to the floor vents is stuck closed.
Cold air return vents are the ones on the wall
thermal vents
It is the Marine :(
No, floor vents will not help in cooling your house since they are only used when your air conditioner is on. Fans are the cheapest way to cool a home down.
The flap that directs sir to the selected vents is jammed or broken...or the switch that controls it is.
thermal vents