The B4000 pickup was part of the Mazda B-Series that included the B2300 and the B3000. The B-Series trucks share their components with the Ford Ranger. In fact, the two vehicles were built on the same assembly line until the B-Series was discontinued after 2009. Replacing the headlight bulbs in your B4000 is a normal maintenance procedure. You can do this at home and save a trip to the service department.
Reach to the headlight switch on the left side of the dash and turn the switch to "Off" before getting started. Turn the Mazda's engine off and remove the key. Open the hood. Put on gloves before proceeding.
Unplug the wiring harness from the back of the headlight. Grasp the plastic retaining cover located behind the headlight. Turn the cover counterclockwise to unscrew it. This gives you access to the bulb.
Pull the bulb rearward to remove it. Dispose of the old headlight bulb.
Place the new bulb in its spot. Attach the plastic retaining cover back onto the headlight bulb. Turn it clockwise to lock it in place.
