Which of the following is NOT an item to inspect for a vehicle's interior?

The inspection of a vehicle's interior typically focuses on elements that directly impact the safety and control of the vehicle while in operation. Steering wheel free play, brake pedal fade, and the condition of seat belts are all critical components that relate to the overall safety and functionality of the vehicle.

Steering wheel free play is important as it affects the driver's control over the vehicle. Excessive play can indicate problems with the steering components, which could lead to handling issues. Brake pedal fade refers to a loss of braking effectiveness, which is vital for ensuring stopping power when needed. The condition of seat belts is crucial as they are a primary safety feature designed to protect occupants during a collision.

Air conditioning functionality, while certainly an important comfort issue for passengers, does not affect the vehicle's operation or safety directly. Therefore, it is not typically categorized as an item for inspection under the parameters of vehicle interior safety checks.