A/C Selector The selector on your temperature control panel that turns your Air Conditioning unit on or off.

Air Bag Assembly A thin, nylon bag and associated parts mounted in the steering column, dash, and/or doors of a vehicle designed to prevent injury or death in case of a collision at speeds greater than 15 miles per hour.

Air Bag Control Module The "brain" behind the airbag system that tells the airbag whether or not to actuate. It contains a device called an accelerometer that measures (and sometimes records) sudden deceleration. The location for this unit varies with manufacturer, but is most often underneath one of the front seats.

Air Bag Detector Basically another term for the Air Bag Control Module. The Air Bag Control Module is the "brain" behind the airbag system that tells the airbag whether or not to actuate. It contains a device called an accelerometer that measures (and sometimes records) sudden deceleration. The location for this unit varies with manufacturer, but is most often underneath one of the front seats.

Air Cleaner Assembly The entire housing for the air filter and associated hardware and sensors. The Air Cleaner Assembly, on older cars with carburetors, is almost always a round, plate shaped steel can mounted on top of the engine. On newer cars, they're more normally a rectangular plastic box, with large hoses connecting it to the engine.

Air Flow Meter Measures the flow of air that the engine is using at any given time, and sends this information to the engine computer for fuel mixture adjustments. Critical for smooth operation and fuel efficiency. Located either in the Air Cleaner Assembly or elsewhere in the engine air inlet system.

Air Injection Pump Primarily used on older automotive emissions control systems in the 70's and 80's, the Air Injection Pump is used to pump more air into the exhaust stream to aid in burning of harmful exhaust particles. Normally mounted on the front of the engine and driven by a belt, it will have a pipe running into the exhaust manifold.

Air Ride Compressor Compressor used to adjust a vehicle's ride height or shock absorber stiffness. Primarily used as part of a retrofit kit for performance cars/low riders, but does come stock on some luxury and high-end performance cars.

Air Ride Control Module The computer that controls the ride of a vehicle with an electronically controlled suspension. May be located nearly anywhere in a vehicle, but will normally be behind the dash or other trim work.

Alternator The alternator is a device that recharges the battery of your vehicle and provides the majority of the vehicle's electricity while the vehicle is running. Normally round or cylindrical, located near the front of the engine off to on side or another, and is belt-driven.