Vehicle Interior Forced Air Extraction, Checking
Representative for the other vehicles, the following illustrates the air ducts in the luggage compartment and through the opening of the luggage compartment side trim panel for an Audi A4 sedan and an Audi A4 Avant. The luggage compartment trim can be different on other vehicles (for example, on an Audi A5 coupe). Refer to LUGGAGE COMPARTMENT SIDE TRIM PANEL, REMOVING AND INSTALLING . The vehicle interior is ventilated the same way on these vehicles.
Air duct to the vent frame of the forced air extraction on a vent frame:
- The air from the vehicle interior flows over the opening in the area of the rear window -arrows- past the rear shelf -A- in the area under the rear shelf -A-.
- The air flows in the luggage compartment via the opening in the plate -B- under the rear shelf -A-.
- Via the opening in the luggage compartment side trim panel (left and right) -C- the air flows out of the luggage compartment behind the luggage compartment side trim panel and from there to the left and right vent frame -D-.
Air duct to the forced air extraction vent frame on an avant:
- The air from the vehicle interior flows via the vent grille -C- (in the area of the rear side windows) -arrows- behind the left and right luggage compartment side trim panels -A and B- and from there to the left and right vent frame -D-.
Checking the forced air extraction vent frame (vehicles with cover in the luggage compartment side trim panel)
-- Open the cover in the left and/or right luggage compartment side trim panel.
Checking the forced air extraction vent frame (vehicles without cover in the luggage compartment side trim panel)
-- Loosen or remove the luggage compartment side trim panel (left -A- and right -B-). Refer to LUGGAGE COMPARTMENT SIDE TRIM PANEL, REMOVING AND INSTALLING .
TIP
- Depending on the version an opening -E- can be installed in the luggage compartment side trim panel (left -A- and /or right -B-). The vent frame -D- can for example be checked via this opening with an endoscope without removing the corresponding luggage compartment side trim panel.
Check forced air extraction vent frames from the outside
- Only perform on vehicles without a cover on the luggage compartment side trim panel, if the rear bumper cover -E- is already removed. If there is a concern due to moisture in the vehicle interior here the air duct to the vent frame behind the luggage compartment side trim panel must also be checked.
-- Remove the rear bumper cover -E-. Refer to BUMPER COVER, REMOVING AND INSTALLING .
Continuation for All Vehicles
-- Make sure left and right ventilation frames -D- are not obstructed.
- The sealing lips in the ventilation frame -D- must move freely and close automatically. Stuck sealing lips can result in fogging of the windshield, rear window, and the door windows. The same is also true for closed or blocked air ducts to ventilation frames -D-.
- To ensure that the sealing lips close correctly, the ventilation frame -D- must be installed on the correct side.
- So that the air can flow behind the luggage compartment side trim panel to the left and right vent frame -D- the space must not be closed or constricted by objects or retrofitted components.
-- Make sure the left and right ventilation frames -A- are not obstructed and that the sealing lips -B- function properly.
- Stuck sealing lips -B- or loose objects in front of the vent frame -A- can lead to damage to the windshield, rear window and the door windows.
- The ventilation frames -A- can only be installed in one position to ensure the sealing lips -B- close correctly.


