Hot air being blown in cabin

Hello all,
I’ve noticed that hot air will blow into the cabin after some time of driving. I suspect it’s from the engine and is coming from a vent back under the radio area I can feel it blowing when I drive. Any thoughts on where it’s coming from and how to stop it?

thank you

 

I would first suggest spending some time under the dash and verify that it is coming from a vent. If so, check for a cable that controls it and why you cannot close it.

 

If I show you a picture, could you give me your advice as to where to look?

 

It probably wouldn't hurt, that will give others a chance to look also.

 

This is the vent

 

If that box is missing a cable operated door a thrifty fix would be to close it for the summer or go to the local car parts lot and find a similar unit.

 

Isn’t the door inside the box?? I can’t tell.

 

The position of the cable does not make sense...A push or pull of the cable does not look like it will not move the damper shaft or damper. Check the movement of the damper assembly and make sure it moves freely and actually moves the damper open and closed...

 

Look at the the part the cable goes through the right side is squeezed tight the left side is not there for letting the cables slide freely and not opening and closing the door is what I think

 

Do any other positions of the hvac system work?