the electronic movement inside, and the air hitting metel
No. You vent air from a sewer line.
you cant so do not turn it on or else your house will catch on fire
Because a vent is closing. Its the fresh air intake closing.
a great down-and-dirty way is to get a can of lysol, turn on fan and "recirculate", which might be "max a/c" in your vehicle, find the recirc intake vent (the vent in the floor area that is drawing air in 'recirc' mode, or not blowing air when vent is on "high", usually on passenger side), turn fan about medium, and spray lysol in intake vent until lysol mist exits the vents. Then shut down HVAC and let the lysol disinfect.
An air admittance vent is a mechanical sewer vent which allows air to enter into the sewage system but does not allow exhaust of sewer gases.
the air vent is cold
your fresh air door is sticking open or closed and the motor is trying to open or close it
An air vent is an opening, sometimes covered by a grate, which allows air to circulate around a room.
It is located under the dash on the drivers side. between the fresh air vent and the firewall. It should be mounted in a clip, mounted to the backside of the vent. Very difficult to get to.
Lower the right lever near the right seat on the transmission hump near the shifter to turn the heat off. Raise it to get heat. Left side is for defrost or foot air. I believe the '69 had a manual lever in the foot heat vent also if you wanted to turn the foot air completely off and still have the air for the defroster.
The purpose of air vent on pipe works of infrastrucure