A ventilation module and related mold assembly for producing, the module being integrated into a vehicle and including a housing defining an open interior which is adapted to secure to a location of the vehicle in order to communicate an exterior with a passenger compartment interior. A flap is hingedly secured along a selected edge in extending fashion across the open interior of the housing, the flap further including first and second side edges and an interconnecting top extending edge which are configured to engage support locations configured along the housing in proximity to the open interior. The flaps are configured to seal against the housing in a first direction to prevent the admittance or backflow of dirty air from the exterior into the interior compartment. The flaps open in a second direction in response to a positive air pressure condition created within the passenger compartment and in order to vent to the exterior the excess air pressure until reclosing upon achieving an air equilibrium condition.