Headlights have a tendency to go out at awkward times, leaving your vehicle with limited or no lighting. The Mazda 3 headlight is easy to access and replace. Learn to do it at home to avoid a trip to a service shop.
Purchase a new headlight bulb. When purchasing a new bulb, give the store clerk your VIN (vehicle identification number) to make sure the bulb will fit your Mazda 3.
Disconnect the vehicle's battery. The battery box on the Mazda 3 can be found on the driver's side of the engine bay, close to the windshield. The battery should be disconnected every time you work with electrical components.
Locate the headlight bulb module, located behind the headlight assembly. The Mazda 3 has ample room to access it without removing any other components. Turn the module counterclockwise to release it.
Remove the bulb by turning it counterclockwise and lifting. Discard the old bulb. Place the new bulb in the slot and turn it clockwise to lock it.
Place the module back into the rear of the headlight assembly and turn it clockwise to lock it back in place.
Make sure you are working in an area with adequate lighting; it will make installation of the headlight much easier.